Design and Modeling of Mechanical Systems—III

In photovoltaic solar cells, p-n junctions have been considered a very promising structure to improve the carrier collection efficiency and accordingly the conversion efficiency. The basic processes for a solar cell to work are the generation of electron–hole pairs, separation, and recombination of those carriers in external circuits. The step of critical importance here is the electron–hole pair separation. The inner piezopotential, formed in the crystal by applying a stress which is called piezophototronic effect, interferes directly in the separation and recombination process, and consequently affects the solar cell performance. Recently, elaborated models including the piezophototronic effect were proposed to simulate metal/semiconductor and a p-n junction based in ZnO, but discussion of results has been limited to the output and the open-circuit voltage. In the present work, we will attempt to extend systematically the modeling of photovoltaic conversion on solar cell. The piezophototronic effect is included both in transport equation and photocurrent. Finally, the experimental results of organic solar cells support our theoretical model. Using the piezoelectric effect created by external stress, our study not only provides the first basic theoretical understanding about the piezophototronic effect on the characteristics of an inorganic solar cell, but also assists the design for higher performance solar cells.

In this paper, the potential of vibration analysis for early detection of fuel injection faults in an internal combustion diesel engine, having six cylinders in line, has been investigated. The main sources of vibration of a diesel engine, as well as the mechanism of propagation of these sources to the engine structure have been presented. Using the tarring screw of the injector, the injection pressure in one of the cylinders has been gradually reduced from its nominal value, respectively, by 10 and 50%. Two signals are acquired using an analog-to-digital dynamic acquisition card. The first is the TDC signal in cylinder 1 measured using an inductive sensor. The second is the vibration signal which has been measured, on the cylinder head of the engine using a piezoelectric accelerometer. The vibration signal has been analyzed in the crank-angle domain, the frequency domain using the Fast Fourier Transformation, and in the angle-frequency domain using the Short Fourier Transform. The analysis of the injection fault signals in the three domains showed that in the crank-angle domain, a visual analysis gives limited information; in the frequency domain, the identification of the cylinder with the faulty injector is not possible; and in the angle-frequency domain, the detection of the injection fault and the identification of the faulty cylinder are possible and not complicated.

Establishment of a new approach for investigating the dynamic behavior of a cracked rotor system is the goal of the present research. This paper provides a breathing crack model of a rotating shaft supported by hydrodynamic bearings. The modeling is based on the hypothesis that a short hydrodynamic bearing, unbalance, and crack defect causes instability and change the dynamic behavior of the rotor. A nonlinear dynamic analysis of the system highlights the interactions, especially, unbalance defect, and crack defect. The global model can be characterized by nonlinear state equations which are solved iteratively by numerical integration. The major interest of presenting this model is that it allows to analyses the effect of a transverse cracks on the dynamic response of a hydrodynamic journal bearing system. Analysis of transverse cracks defects, on the stability and the dynamic behavior of the rotor-bearing system and further certain operating conditions were performed by applying bifurcation diagrams, Poincare section, the trajectory center of the journal, and power spectrum.

Vibration energy harvesters (VEHs) provide an efficient solution for implementing self-sustained low power microelectromechanical systems. When operating linearly, unimodal VEHs have a narrow operating bandwidth. Consequently, their performances can be significantly reduced if the VEH resonance frequency and the excitation frequency do not coincide. In order to overcome this issue, we propose an optimized nonlinear multi-degree of freedom (MDOF) vibration energy harvesting system based on electromagnetically coupled beams. The dynamic equations of the equivalent discrete nonlinear MDOF model, which include the magnetic nonlinearity, the mechanical nonlinearity due to the mid-plane stretching of the beams and the electromagnetic damping, are derived and numerically solved using the harmonic balance method coupled with the asymptotic numerical method. A multiobjective optimization procedure is defined and performed using a non-dominated sorting algorithm (NSGA) in order to find the optimal solution in terms of performances by taking advantage of the nonlinear coupling and the modal interactions. The proposed strategy enables scavenging the vibration energy with a frequency bandwidth ranging from 22 to 32 Hz and a normalized harvested power of 312 µW cm−3 g−2.

The Direct Normal Irradiance (DNI) is the fuel for all concentrating solar energy systems. It could either be measured by means of highly sophisticated instruments or computed using DNI models. These models utilize meteorological and atmospheric parameters as inputs to predict instantaneously the DNI in regions where no measurements are available. This paper presents a performance analysis of the Ineichen, Iqbal and Solis models to predict the direct normal irradiance when we present low-quality input parameters. The models have been used to predict DNI in a southern Tunisian region. The prediction results have been compared to measurements. The sub-hourly statistical evaluation of these models shows the following errors: when the DNI is higher than 700 W/m2 (at noon), the Iqbal model is the most accurate prediction model with a relative root mean square error (rmse%) equal to 9.82%. The same model has recorded the best accuracy when DNI is lower than 700 (the sun is close to the horizon), the rmse% reaches 27.88%. Such results clearly show that presenting a limited quality inputs to the models, at the limit, can be accepted to perform DNI prediction at noon but they are not suitable to predict effectively the DNI when the sun is close to the horizon.

This paper focuses on the examination of macrostructure and microstructure of friction–stir-welded AA2024-T3 joints. The tool rotation speed and the traverse speed, the most important process parameters of FSW, are evaluated through tensile strength test and microhardness test. The analysis of microstructure showed a zonal transition from the base material to a heat-affected zone; a thermo-mechanical affected zone and a nugget zone in the center of the weld with a grain sizes were different. From this investigation, it is found that the tensile strength and percentage elongation increase with the traverse speed decreasing, whereas it increases as tool rotation speed increases up to the 750 rpm and then decreases with further increase of tool rotation speed. As a result, increasing the tool rotational speed leads to the increase in hardness nugget zone than that in the thermo-mechanically affected zone and affected zone. The microhardness was strongly dependant on tool rotation speed and it increases with the increasing of this parameter from 600 to 750 rpm.

This paper deals with the investigation of friction and wear mechanisms involved when scratching parallel to fiber orientation of unidirectional glass fiber reinforced polymers (UD-GFRP) composite. A single indenter scratch test (SST) was performed at room temperature and constant sliding speed, using high speed steel conical indenter. The dominant damage modes owing to SST were inspected at different attack angle and load using scanning electron microscope (SEM). The apparent friction and the damage modes were investigated as function of the test parameters, particularly, the attack angle and the normal load. The experimental findings reveal that the attack angle has a most important role in controlling apparent friction if compared with applied normal load. However the wear mechanisms were more sensitive to both attack angle and normal load. The correlation between wear modes and tribological parameters was emphasized and the scratch map was parallel to fiber orientation built. Six domains were identified and the different wear mechanism transitions were detailed.

The lively field of assembly line problem often has a significant impact on the performance of manufacturing systems. In this context, Assembly Line Balancing Problems (ALBPs) are widely cited in the literature. The ALBP is one of the most important problems among the other problems of assembly lines like designing and managing. The fundamental ALB Problem (ALBP) is the way of getting an optimal assignment of tasks to the stations respecting well-determined constraints and reaching certain objectives. In the previous research, there are many studies on developing methods for solving Simple Assembly Line Balancing Problems (SALBP) and their various extensions. Each extension is motivated by several real-life applications. This paper presents a new extension of SALBP-2, so-called Multiobjective Assembly Line Resource Assignment and Balancing Problem of type 2 (MOALRABP-2). The problem is a tri-criteria one, which aims to minimize simultaneously the following objectives: the cycle time, the mean absolute deviation and the cost per time unit (hour) of a line for a fixed number of stations to satisfy the constraints of precedence between tasks and compatibility between resources. A new version of Multiobjective Evolutionary Algorithm (MOEA) named Hybrid MOEA (HMOEA) is elaborated to seek a set of diverse optimal solutions. In addition, the MOEA parameters are optimized using the Taguchi method. The effectiveness of the HMOEA was assessed through a set of problems. The results comparisons show a quite promising higher performance for the HMOEA.

Dynamic study of Darrieus turbine bevel spur gear subjected to transient aerodynamic loads is carried out in this study. The aerodynamic torque is obtained by solving the two-dimensional unsteady incompressible Navier–Stocks equation with the k-ω Shear Stress Transport turbulence model. The two-dimensional computational model is validated with experimental results. A three-dimensional dynamic model of one-stage bevel gear system is developed. The periodic fluctuations of the gear meshes’ stiffness and the unsteady aerodynamic torque fluctuations are the main sources of excitation for the gear system. The originality of our work is the correlation between complex aerodynamic phenomena and the mechanical gearing system vibration. The effect of the rotational speed on the overall dynamic behavior of the Darrieus turbine is also discussed. The present study shows that the rotational speed significantly affects the aerodynamic efficiency. Whereas, there is a small influence on the dynamic response of the bevel gear system.

The modelling of mechanical systems plays a primordial role in the study of structural dynamics and the vibrations that result. One presents in this work the modelling of a road bridge by a continuous multi-span orthotropic plate supported by point elastic supports along the longitudinal direction and with three-point elastic supports on the transversal direction. One has found that when the parameter of the elastic support is greater than zero, which means that the elastic supports have a high rigidity; the behaviour of the elastic supports tends towards the behaviour of the rigid supports. Note that the values of the bridge natural frequencies switch between those of a free-free bridge for the case of a lower support’ parameter and those of a simply support bridge for the upper case. Finally, one carried out the generalized modelling of the behaviour of a road bridge supported by point elastic supports for N spans by using the computer tool for carrying out different calculations and makes it possible to have a view of many cases of Road Bridge properties.

The ship propulsion system is a nonlinear and uncertain system. To overcome these constraints, in order to synthesize a powerful command, the multimodel control is promising. This paper deals with the modeling and multimodel control of complex uncertain systems. The approach is based on the principle of generating model bases, which can be local or generic, determined according to procedures using Kharitonov’s algebraic approach. The evaluation of the relevance of the models is ensured by means of validations calculated on line by referring to the responses of the process. Such validities are used to generate the multimodel control according to a strategy by fusion. Two fusion methods are then proposed: A merge at the level of the elementary commands and another at the level of the control parameters. This work deals with the development of a model base, as well as the synthesis of a multimodel control law. In this sense it is proposed to study the electric propulsion of ships as well as its composition. Next, we propose a technique for modeling the electric propulsion system of a ship and synthesized a multimodel control law. Finally, we will model the propulsion system based on a synchronous motor with permanent magnet and synthesize a law of control according to the multimodel approach.

The metric distance error between the calculated point and the real point in 3D measurement coordinate system is due to optimization methods carried out in 2D image plane. Euclidian image-based 3D reconstruction is carried out in three major steps, geometric primitive extraction, correspondence, and triangulation. Extraction and triangulation are purely geometric tasks but the correspondence step is a challenge in precision. In this paper, we study 3D object reconstruction based on a set of 2D images. We used a robot arm to move accurately the camera and we study the influence of the motion. It has been demonstrated that the impact of a correspondence error on the reconstruction accuracy of a 3D images-based reconstructed point may vary depending on the image capture strategy. Two modes of motion have been adopted. The first is an axial mode making the camera close or far from the object acting like a zoom. The second mode is lateral where the camera moves parallel to the object. It has been shown that axial mode leads to greater errors compared to the lateral mode. The impact of the geometric parameters of photographing on images-based 3D reconstruction error is also discussed.

The dynamic behavior of structures subjected to moving loads has aroused particular interest in the field of mechanics. In this field, theoretical studies were presented by several researchers to estimate the dynamic responses of these structures. The moving loads on the beams cause deformations. These deformations must remain in the elastic domain in order to allow the beam to fulfill its role. For this purpose, the determination of the beam deformations of the beam under a moving load is imperative. The main objective of this work is to study the deflection of simply supported beams under moving loads. Analytical and numerical models have been developed to describe the behavior of an elastic IPE200 beam. In the analytical and numerical methods, the principle consists in formulating the dynamic equations of motion. This method allowed us to determine the deflection of the beam subjected to a moving load. The results obtained by the two methods are compared.

The malfunctioning of combined sewer systems can lead to an uncontrolled discharge of wastewater into receiving environments causing very serious pollution. The protection of these environments requires a control of the flows and the pollutants concentration. This approach takes into account the hydraulic operation of the sewer systems and the mechanism of the pollutant transfer. In this work, we are interested in a portion of a sewer system of Monastir city in order to reproduce the hydraulic phenomena that occur there. The numerical study was treated using “ANSYS Fluent” software. The standard k-ε turbulence model and the multiphase VOF model are used in this work. The exploitation of the results is mainly carried out on the flow rates, the water velocities, and the free surface. Then, we described the evolution of the pollutant concentration, the free surface, and the sediment deposition by examining the various mechanisms of the turbulent flow.

This paper is devoted to propose and apply a surrogate-based multidisciplinary design optimization (MDO) method on stiffened panels with several substructures and objectives. This method combines Kriging Surrogate Model (KSM), which is used to predict the exact responses of objectives and constraint functions, and an Improved Multi-Objective Collaborative Optimization (IMOCO) to solve the MDO problems. In the KSM-IMOCO scheme, each exact optimization problem at structure and substructure level is replaced by a metamodel to limit the computational burden. To demonstrate the applicability of the proposed KSM-IMOCO method, we treat an engineering example of kind stiffened panel. Results obtained from the application of the KSM-IMOCO approach on optimization problem of a stiffened panel kind L are compared with the traditional optimization (TO), without passing by the approximation tools, and it has been shown the sovereignty of the proposed KSM-IMOCO method. These results indicate that the proposed KSM-IMOCO method significantly reduces computational burden, and improves the convergence rate for solving the exact multidisciplinary optimization problem.

Through this work, a compensation of the GMS friction in two degree of freedom planar robot manipulator is presented. The compensation is done using an online least square estimator to identify the friction force and then to be injected in the control law. The least square estimator has a linear formulation over the unknown parameters. However, the dynamic equation of the GMS friction needs a switching function to guarantee the transition between its two phases. This switching function is based on the unknown parameters. Therefore, the problem of the switching function was solved using an approximated switching function based on a prior values of the stiffness and the Stribeck coefficients. The compensation of the friction force is validated using an experimental apparatus that generate an experimental position, velocity and acceleration which are used as desired trajectories. The experimental friction force was injected in the joints of the robot manipulator modeled in MATLAB. The performance of the system without compensation of the friction is compared to the performance with compensation of friction force. The performance of the approach proposed showed a good tracking of the desired trajectories using a simple proportional derivative controller.

In the past decades, research was directed towards the use of plant fibres instead of synthetic fibres as reinforcement of composites. Due to their high specific mechanical properties coupled with low cost and their wide availability at the European scale, flax fibres could be considered as the most interesting plant fibres. Experimental tests carried out on flax fibre-reinforced composites have shown that these latter are characterized by a nonlinear viscoelastic–viscoplastic behaviour. In this paper, our work was focused on modelling the elastic–viscoplastic behaviour of a quasi-unidirectional flax fibre-reinforced composites. First of all, we developed a three-dimensional elastic–viscoplastic model taking into account the orthotropic elasticity and the anisotropic viscoplastic behaviour of quasi-unidirectional flax/epoxy composites. Then, based on tensile tests at different strain rates, we identified the isotropic hardening using an optimized exponential Johnson–Cook law. The model was validated against experimental data. Finally, we implemented the behaviour model in a UMAT procedure of the finite element code ABAQUS/Implicit and simulated low-velocity impact behaviour of a flax/epoxy circular plate. Simulation has shown that the impact velocity has a great influence on the behaviour of flax fibre-reinforced epoxy composite plate.

This paper focuses on a dynamic simulation of a partial unloaded walking motion within a gait training machine using the simulation tool: MATLAB SimMechanics. This training machine emulates the walking through: a body weight support device and a cable driven leg manipulator. The human body is modeled as a multi-segment articulated mechanism. Length and inertia specifications of body segments are determined based on anthropometric data. The main external forces acting on the human body are the unloading force applied to the upper body, the ground reaction force and the actuation wrench produced by the leg manipulator. The Matlab SimMechanics software is used to simulate dynamically the walking motion in order to calculate the required wrench to drive the lower limb during a cycle of a normal gait. In fact, the human body is created according to kinematic and dynamic modeling, and besides, the external forces are applied to the body segments. Considering a body having a mass of 100 kg and a height of 1.7 m, curves of actuation wrench are retrieved.

Magnetic properties of soft ferromagnetic materials are very sensitive to high mechanical and thermal stresses. In order to characterize its changing magnetic behavior, this chapter deals with the study of the choice of the performant magnetic hysteresis model, which can be able to model perfectly the thermo–magnet–mechanical coupling of a fully processed non-oriented Fe-3 wt%Si steel sheet. Therefore, our study focuses on identifying the model parameters for different static models by application of an appropriate optimization technique. For simple models, a direct identification is used, and the GA technique will be applied for complex ones. The performance of the model depends on the error that it presents with the measurements as well as its ability to reproduce properly the experimental hysteresis studied. Our study is based on the static models of Rayleigh, Potter, Frolich, and Preisach. Identification results show that the Preisach and Frolich static models can model the hysteresis curve of the Fe-3 wt%Si steel sheet more accurately than the other models studied.

This chapter deals with the static behavior of carbon nanotubes reinforced functionally graded cylindrical nanocomposite panels. In fact, with the rapid progress of nanotechnology, the use of as kinds of reinforcements in composite structures has attracted the attention of many researchers in the last years. The modeling is based on the Kirchhoff–Love finite element model which constitutes a convenient model to describe the kinematics of shells especially when thin structures are investigated. For the constitutive material law, the modified rule of mixture is adopted which introduces some efficiency parameters to take into account the dependence scale of carbon nanotubes. Four types of distributions of carbon nanotubes are considered which are uniformly and three functionally graded profiles. Static analyses in terms of deflections are presented in order to show the effects of volume fraction of carbon nanotubes as well as the length-to-radius ratio on bending behavior of functionally graded shell structures reinforced by carbon nanotubes. The obtained results are compared to those available in the literature leading hence to outline the performance and the accuracy of the presented model.

This chapter presents a static behavior of geometrically nonlinear of Functionally Graded Material (FGM) thin shell structures. The proposed model, based on Kirchhoff shell element, consists in annulling the transverse shear deformation. The developed model is generalized to plates and shells such as cylindrical, conical, spherical, and hyperboloid shells. Material properties are assumed to be graded through the thickness by varying the volume fraction of the ceramic and the metallic constituents using power-law distribution. Numerical results are presented for pinched hemisphere. The load parameter is plotted versus the deflection in the two loading point A and B. Numerical results are compared with previous works. A good agreement between the present results and the literature confirms the high accuracy of the current nonlinear model for an isotropic material. The load parameter of FGM pinched hemisphere is plotted versus the deflection at the loading points by varying the power index from metal to ceramic. The deflection gap between the loading points A and B increases with the power index.

Based on the First-order Shear Deformation Theory (FSDT), this paper performs the geometric nonlinear analysis of Functionally Graded Material (FGM) shell structures. In this theory, a constant transverse shear deformation is considered and a shear correction factor is required. In order to avoid transverse shear locking, the assumed natural strain method (ANS) is incorporated in the finite element formulation. In addition, the variational principle is used to obtain the governing equation and the Newton–Raphson iterative method is adopted to solve the nonlinear equations. The constituent of FG shells consists of ceramic and metal. These constituents are graded through the thickness by varying the volume fraction using a power-law distribution. The post-buckling responses of simply supported cylindrical panel are examined. The effects of volume fraction are also investigated. Numerical results are compared with previous works. A good agreement among the present results and the literature confirms the high accuracy of the current nonlinear model.

Fatigue damage of short glass fiber-reinforced composite is a quite complex phenomenon, and a large research effort is being spent on it these days. Furthermore, fatigue damage in such materials, fatigue damage kinetic exhibits three stages, namely: (i) matrix microcracking and damage initiation, (ii) coalescence and propagation of microcracks and (iii) macroscopic cracks propagation up to material failure. The proposed model is based on the stiffness degradation rule of short glass fibers-reinforced polyamide 66. This new versatile phenomenological fatigue damage model attempts to predict fatigue damage growth in its three stages. The characteristics of damage growth and accumulation of short glass fiber-reinforced polyamide 66 under fatigue bending loading were studied in this paper. Experimental data from bending fatigue tests were used to identify the model parameters. Results showed that this model is capable of describing the three stages of damage evolution of theses composite materials. Furthermore, the predicted fatigue life is in good agreement with the experimental ones.

As a preliminary important phase for a hydraulic network analysis procedure, loops identification process is studied in this paper by presenting an automated algorithm to select a set of independent loops for the network equilibrium. Through the presented study, the hydraulic network is modeled as an undirected graph edges-vertices. Also, to take into consideration the mechanical characteristics of the network, weights are assigned to pipes based on their hydraulic resistances. The assigned weights are taken as a selection criterion for loops identification. A numerical code under Matlab environment is generated and the established framework is tested on a set of real case networks. The obtained results are compared to those issued from previous researchers. Thus, the framework has proved its efficiency in identifying a set of independent loops even for complex network topologies. The mutual independence of the obtained loops is verified which allows to use the presented algorithm to build a general automated framework for water distribution network analysis.

Condition monitoring of industrial processes can minimize downtime and maintenance costs while enhancing the safety of operation of plants and increasing the quality of products. Multivariate statistical methods are widely used for condition monitoring in industrial plants due to the rapid growth and advancement in data acquisition technology. However, the effectiveness of these methodologies in real industrial processes has not been fully investigated. This paper proposes a CVA-based approach for process fault identification, system modeling and performance estimation. The effectiveness of the proposed method was tested using data acquired from an operational industrial centrifugal compressor. The results indicate that CVA can be effectively used to identify abnormal operating conditions and predict performance degradation after the appearance of faults.

Flexible forming with rubber pad is a forming technique that is commonly used in the aeronautic and automotive industries to produce parts with complex shapes from thin sheet metal. The purpose of this chapter is to compare between using flexible punch or flexible die in sheet metal forming with rubber pad. A finite element simulation is carried out to predict the behavior of the flexible stamping process of aluminum sheet metal with the two techniques of forming. For the sheet metal, an elastoplastic constitutive model is adopted and implemented in ABAQUS/Standard software via UMAT subroutine. However, a Mooney–Rivlin hyperelastic model is adopted for the rubber pad. Results predicted numerically consist of comparing the variation of some key parameters process using two deformation styles in order to produce safety parts without localized severe deformation. It was found that using rubber as flexible die may reduce the thinning rate and values of equivalent plastic strain in the formed part. Also, based on the Forming Limit Diagram (FLD) analysis, using flexible die instead of flexible punch may successfully form part without necking and micro crack and without localized severe deformation that can lead to fracture.

Incremental sheet forming is a flexible process that benefits from the evolution of CNC machine tools; it usually uses a three-axis NC milling machine even for asymmetric parts. This paper presents a numerical simulation of single point incremental forming (SPIF) process of asymmetric part, manufactured using two types of NC machines: NC milling machine and NC turning machine. A finite element model (FEM) is developed by using the commercial FE code ABAQUS/Explicit. An elastoplastic constitutive model with quadratic yield criterion of Hill’48 and isotropic hardening behavior has been considered for the sheet metal. A user material subroutine (VUMAT) is used to implement this material behavior. Results including thickness variation, deformed shape, and forming force along Z-axis are presented. A remarkable difference has been observed in the results obtained from the use of these two machines. In fact, NC lathe machine is a good alternative to manufacture asymmetric parts and many advantages can be mentioned, such as the remarkable decrease of thinning and vertical force which improves formability during the ISF operation.

One of the major factors that can affect the vehicle performance and the passenger comfort is the road disturbance. The objective of this study is to identify this road excitation acting on the vehicle using blind source separation (BSS) technique which is the independent component analysis (ICA). This method is applied on a nonlinear suspension system since the vehicle has a nonlinear behavior. The studied system is a quarter-car model, it contains the most basic features of the vertical model of the vehicle. The estimation method is very efficient due to its simplicity and short computing time. It is based only on the knowledge of the dynamic responses of the system under study. The validation of the obtained results using the ICA method was done by computing three performance criteria. Finally, a good agreement is found between the original signals and the estimated ones.

This paper propose a procedure to estimate uncertainties in measurement process using the coordinate measuring machines (CMMs) in the aim to inspect manufacturing surface parameters. On these machines, surfaces must be measured by a number of points higher than the parameters necessary to their mathematical definitions. However, the representation of the same element can be very different according to the average materials and the protocol used during the measuring step. The real contact points between the stylus and the measured surface being unknown, one substitutes to it a measured point. This last is calculated starting from coordinates of the stylus center, the normal vector (n_i), and the stylus radius, which generates uncertainty on the real position of the measured point. This uncertainty is even propagated on the inspected surface parameters. The procedure proposed by this work permits to estimate the uncertainties on the surface parameters which characterize the geometrical surface, a data processing model in Visual Basic 6 was developed which makes it possible automatically to determine the whole of these parameters, and thus their uncertainties.

In this paper, a multi-objective, multi-period, multi-product stochastic model for a multi-site supply chain planning problem under demand uncertainty is proposed. The decisions to be made include the amounts of product to be produced, the amounts of products to be transported between the different sites and customers as well as the amounts of inventory of finished or semi-finished products. The developed model aims simultaneously to minimize the expected total cost, to maximize the customer demand satisfaction level and to minimize the downside risk. The e-constraint method is applied to solve the considered model and to generate the set of Pareto optimal solutions. This set of Pareto represents the trade-off between the different objective functions. Then, an integrated approach of the Analytic Hierarchy Process (AHP) and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) methods is applied in order to select the best compromise Pareto solution. A numerical example is presented to illustrate the proposed approach.

Reciprocating compressors are vital components in oil and gas industry, though their maintenance cost can be high. The valves are considered the most frequent failing part accounting for almost half the maintenance cost. Condition-Based Maintenance and Prognostics and Health Management which is based on diagnostics and prognostics principles can assist towards reducing cost and downtime while increasing safety and availability by offering a proactive means for scheduling maintenance. Although diagnostics is an established field for reciprocating compressors, there is limited information regarding prognostics, particularly given the nature of failures can be instantaneous. This paper compares several prognostics methods (multiple liner regression, polynomial regression, K-Nearest Neighbours Regression (KNNR)) using valve failure data from an operating industrial compressor. Moreover, a variation about Remaining Useful Life (RUL) estimation process based on KNNR is proposed along with an ensemble method combining the output of all aforementioned algorithms. In conclusion, it is showed that even when RUL is relatively short given the instantaneous failure mode, good estimates are feasible using the proposed methods.

Most of the researches describe models of gearboxes under stationary operating conditions. However, considering the real situation, the assumption of stationarity cannot be kept longer because during service, gearboxes usually run under fluctuating load conditions. The purpose of this chapter is to study the influence of time-varying loading conditions on a spiral bevel gear dynamic behavior in presence of a local damage. The speed–torque characteristic of the driving motor is considered. The load variation induces speed variation, which causes variation in the gearmesh stiffness period. Using an implicit Newmark’s time-step integration, the dynamic response shows impulses corresponding to the meshing of the cracked tooth; their amplitude level depends on the amplitude of the load. In order to put in evidence the time-varying load effects, spectral analysis is unsuited and time–frequency analysis is used instead. The horizontal lines over wide frequency band corresponding to each mesh period of the defected tooth are observed.

This paper presents a first-order solid-shell element for the post-buckling behavior of functionally graded material (FGM) structures based on the enhanced assumed strain (EAS) with five parameters. The EAS three-dimentional finite element formulation presented in this paper is free from shear locking and leads to accurate results for distorted element shapes. The transverse shear strain is formulated by the assumed natural strain (ANS) method, which ensures a constant distribution through the thickness and requires the introduction of shear correction factors. The transverse shear correction factors are calculated using a computational algorithm based on the static equilibrium and energy equivalence between the shear energy of the shell and the energy from three-dimentional theory. Material properties are varied continuously in the thickness direction according to different distributions. This finite element is used to study the post-buckling behavior of FGM structures and to investigate the influence of same parameters on post-buckling. Comparisons of numerical results among existing ones show the performance of the developed elements.

This paper considers the reliability analysis of mechanical system, especially wind turbine system. Optimization of horizontal axis wind turbine performance is confronted by the aerodynamic complexities such as the instability of the energy source, randomness of loads. The objective of this work is to study the system reliability taking into account random input parameters of the aerodynamic part. It is assumed that the probability law distribution of random parameters is known. The influence of random input parameters on dynamic reliability is evaluated in this study. In order to improve product reliability, an efficient computational method based on the first- and the second-order reliability method (FORM/SORM) has been investigated. For more accuracy, results obtained by the proposed approximation methods are compared to Monte Carlo reference results. These three methods are developed in reliability approach to calculate the failure probability and the reliability index of the studied wind turbine system.

In this paper, we are interested in the change sustained by the topology transformation and in introducing the notion of variable topology of dynamics systems. We are also interested in using substitution to model complex patterns by applying the MGS language (General Modeling System). This later is applied to a 2D piezoelectric truss structure. In fact, the process has been validated since the modeling by using the KBR topological graph, and then by using MGS language, it shows the same result. The major interest in presenting this model of piezoelectric structure is that it contains both electrical and mechanical parameters, and this allows us to treat it as a mini-mechatronic system (actuator and sensor). Considering that any system which is complex is legible to be represented by a topological graph, and knowing that each component of the mechatronic system has its local behavior’s law, so the process that applies to any mini-mechatronic system can be extended later to complex systems. This work highlights the importance of the MGS language, and it also makes the topological graph modeling more flexible. Moreover, we can do the modeling smoothly by changing the topological structure without modifying the behavior’s law, but simply by modifying the topological structure.

The present paper consists first in developing mathematical models to predict stress concentration factor of a carbon fiber reinforced epoxy. Based on response surface method (RSM) a mathematical model has been determined, in which three factors with three levels are implemented. Carbon fiber content, fiber angle, and stress loading are chosen as the main input parameters in this study, which are very significant and rarely considered. The stress concentration factor is considered as output response which is evaluated through finite element study. Second, Minitab statistical package was used to analyze the numerical results and to investigate the effect and the interaction of different factors. An empirical relationship was developed based on the RSM approach for correlating the stress concentration factor with predominant process parameters. The proposed approach can be used as a powerful and an interesting method for engineering design, to determine the stress concentration factor behavior of a carbon fiber reinforced epoxy.

As a new class of metallic foam materials have attracted increasing interest in different fields of engineering. They are particularly versatile because of their interesting mechanical and physical properties: relative low density makes it possible to obtain a high stiffness/weight radio, existence of cavities results in the abilities of energy absorption and of damping, and also gives them thermal and acoustic insulation properties. As a well-known material for reversible inelastic deformation, shape memory alloys (SMA) have been paid attention on over last few years. They possess two important properties: superelasticity and shape memory effect. Cellular structures in SMAs are particularly interesting for their potential to provide superelasticity and shape memory effect in a lightweight material. In this work, 3D foam CAD structure of NiTi material is reconstituted using ellipsoid cell units. A “taking” and “placing” algorithm based on uniform distribution and normal distribution is adopted for the reconstitution process of Representative Volume Element (RVE). In the RVE, dimensions, positions, and orientations are all random. A constitutive model for shape memory alloy including phase transformation, martensitic reorientation and twins accommodation is used to simulate by the finite element analysis the superelastic behavior of the SMA foam. In order to show the efficiency of the proposed methodology, some applications are presented to simulate the compression of shape memory alloy foam. The effects of porosity, size, orientation, and ratio of long and axes short of the unit cell on the superelastic behavior of porous material are discussed.

The paper presents an investigation of the mechanical fatigue behavior of a bio-based composite with an interleaved natural viscoelastic layer. The material used is a unidirectional laminate with different orientations. It is composed of a GreenPoxy resin reinforced with long flax fibers. A viscoelastic layer made of natural rubber has been introduced at the middle layer of the laminate. Different configurations of unidirectional specimens were tested in static tests. The mechanical properties such as the characteristics at failure of the structures with and without natural rubber were determined and compared. The effect of the insertion of the viscoelastic layer in the studied composite on the stiffness, hysteresis loops and loss factors were investigated during cyclic fatigue tests. A comparison of the fatigue behavior of the composite with and without viscoelastic layer was made. The results show that the composite with an interleaved natural viscoelastic layer presents an interesting damping properties considering the high values of the loss factors obtained from cyclic fatigue tests.

The interfacial fracture of adhesively bonded structures is a serious issue for the widespread application of a variety of modern industries. For many manufacturing applications such as automotive structures, bond line thickness can vary considerably. This factor influences adhesively bonded joints performance. Therefore, its effect has to be examined experimentally and should be taken into consideration in the design of adhesive joints. Most of the results from the literature are for usual structural epoxy adhesives, which are usually formulated to perform in thin sections. However, polyurethane adhesives are designed to execute in thicker sections and might have a different behaviour as a function of adhesive thickness. In this study, an experimental procedure is undertaken to characterise the effect of different adhesive thicknesses between aluminium substrates on the mechanical behaviour of a one-component polyurethane adhesive. The mode I fracture toughness of the adhesive was measured using double cantilever beam (DCB) tests with various thicknesses of the adhesive layer ranging from 0.3 to 2 mm. The fracture energy, G_IC, was found to be directed by the thickness of the adhesive layer. It increased linearly up to 1 mm adhesive thickness and then it decreases.

In this study, TiO₂ nanoparticles coatings were prepared on 316L stainless steel substrate by electrophoretic deposition (EPD) process. The morphology and composition were investigated, respectively. The influences of calcination temperature on the wear performance of coated films were also examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). A novel experimental process to improve the wear resistance was investigated. The energetic wear coefficients of wear were also studied. It was observed that the morphology and structure change with the heat treatment. The findings of scratch test showed that the calcined coating exhibited the ability to higher critical load. The relation between wear volume and dissipated cumulated energy was established for calcined and coated thin film, and the energetic wear coefficients of wear were deduced. The results prove that the heat treatment appreciably improves the wear resistance. Obviously, the calcined coating reduced the energetic wear coefficient, which enhanced the resistance to fretting wear.

Global dynamics of a coupled system are synthesized using a substructuring technique based on the transfer functions of the subsystems. In this chapter, the substructuring method was applied in transmission system. The Frequency-Based Substructuring (FBS) methods are considered to identify the dynamic behavior of a structural system. Impedance coupling technique is applied to a double reducer stage, which is based on the Frequency Response Functions (FRFs) of each substructure and constraint conditions in the connection coordinates. The FRF-based substructuring technique has been previously proposed for computing the vibration modes of complex structural system by coupling the FRF of each subsystem. The effect of damping on substructuring method was discussed. Finally, the coupling technique is validated by comparing the present results with the full system ones. The major interest of using this method is that it allows replacing each subsystem by another subsystem without repeating the computation of the full system.

To understand the behavior of marine structures when submitted to the action of waves, it is necessary to assess the pressure field exerted on these structures. This chapter aims at dealing with the numerical modeling of the second-order wave forces acting on a marine structure in finite water depth. The numerical approach consists in using the finite difference method to compute the fully second-order Stokes wave problem applied to a three-dimensional domain with fixed vertical cylinder. To simplify the meshing task, the fluid domain has been decomposed into subdomains. To ensure the continuity of the transformations and the velocity of these transformations at the level of the contact zones of the subdomains, additional boundaries conditions are required. The results provided in this chapter are to expose the numerical results of the water wave impact on the offshore structure for different water depths and wave heights.

In this chapter, a comparison between a number of turbulent models is done in order to investigate turbulence modeling in a turbulent round jet flowing into a counterflow stream. For this purpose, three turbulence closure models are tested: Standard k-ε model, k-ε RNG model, and RSM model. The studied cases of jet-to-counterflow velocity ratios are ranging between R = 3 and R = 15. Velocity and concentration fields are predicted through the centerline velocity and dilution decay along the downstream jet axis. Predicted results are compared with available experimental data from the literature. It is found that the three tested models behave in a similar way in the first region, however, in the further region, a difference between curves from different models appears. This discrepancy seems to depend on the jet-to-current velocity ratio. The k-ε models are found to underestimate the experimental data, while the second-order closure model RSM is found to be the best model to predict the jet diffusion.

This paper is concerned with the localization of structural forces acting in 2D plate at medium and high frequency ranges, through an inverse method based on energy quantities. An energy-based method, called simplified energy method (MES), has already been proposed to predict the energy density field repartition for structural–acoustic problems in mid- and high-frequency ranges. In order to illustrate but also to present one of the applications of this method, this paper presents a formulation to solve inverse structural problems. The main novelty of this paper is to localize the vibration sources in plates, thanks to experimental data of energy densities. The injected forces localization was obtained in the mid–high-frequency range. Experimental investigation was performed to test the validity of the presented technique using different positions of the shaker and measurement points. The experimental results show that the IMES method has an excellent performance in localizing the input forces.

Nowadays, companies are developing more and more collaborative projects, and hence the need to exchange data with many partners, contractors, subcontractors, suppliers, and customers. So, to establish successful collaborations, they must ensure the relevance, coherence, and especially the security of exchanged data. But the Computer-Aided Design (CAD) systems still have gaps that need to be corrected in order to improve the productivity of the design process: they offer few solutions to maintain data consistency within the digital model. Adding to that poor management of changes, the user has to manage the consequences of each change manually. This research explores the role of mates’ assembly, as defined in CAD systems, as a key to maintaining the links between parts in the assembly. In this work, we propose the CAD Assembly Management Model that is based on reference elements, in order to maintain mates between CAD entities when a part is modified by a partner and then reinserted into the assembly CAD, and then propagate changes.

Due to the need to reducing the cost of construction and minimizing the environmental impact in producing, a Doum palm fiber has been used as a reinforcement for plater mortar. The objective of this work is to study the mechanical properties of plater mortar reinforced with varying length and mass fraction of Doum palm fiber. However, naturel fiber have been affected by the Alkali environment of mortar, to avoid this problem an alkali treatment of fiber with sodium hydroxide solution of 1% concentration has been used in order to reduce the effect of alkali attack. In this framework, five-fiber contents (0.5%, 1%, 1.5%, 2%, and 2.5%) by weight and three types of fibers (powder fibers, mixture fibers, and long fibers) have been used. The experimental investigation depicts an improvement of flexural strength for a fibers content equal to 1% for powder fibers and mixture fibers and 0.5% for long fibers. This improvement is due to the alkali treatment which removes the impurities in the fibers. For compressive strength, for 2% of treated Doum Plam fiber, it increase about 4.41%, 9.57%, and 1.26% respectively for powder, mix, and long fibers. Only samples with treatment fibers show an enhanced flexural and compressive strength. Thus, the alkaline treatment is a suitable choice to avoid fiber degradation in the alkali environment.

Particle damping is an emerging technology among passive devices for furnishing high damping of structural vibration, particularly in harsh environment, through the use of granular particles filled within an enclosure. In this work, we investigate experimentally the effect of acceleration amplitude, mass ratio, volume package, and type of material on the dynamic behavior of the particle damping to yield a thorough understanding of the attenuation mechanism played within such dampers. Experimental trials are realized within a rigid enclosure attached to a shaker and partially filled with particles. An analytical model based on the inelastic bouncing ball model (IBBM) is also developed in order to describe the nonlinear behavior of particle dampers. Our measurements reveal that the loss factor only relies on the total mass of the incorporated grains and on the driving magnitude. Further scaling of the loss factor, for all measurements, by the mass ratio led to a universal curve dependent only on the acceleration magnitude. A good agreement between the analytic model and the experimental results was verified.

Helicopters have been extensively employed as a versatile tool in modern society, thus guaranteeing operation safety and flightworthiness has always been our top-tier concerns. However, many accidents indicate that current helicopter health and usage monitoring system (HUMS) are not accurate and effective enough to fulfil this goal, especially for detecting an imminent planetary bearing fault (CAA Authority 2006). To study this case and address such issues, an experiment was undertaken with a special rig, comprising of real helicopter main gearbox (MGB) and dynamometer as a variable load. Defects of different sizes were seeded at the outer race of bearings inside second epicyclic planetary module. Vibration signals of different test conditions (input speed, load and defect sizes) were recorded for post-processing. Measured vibration data contains overwhelming background noise and planetary gear meshes, making it cumbersome to identify the bearing defect. Various signal processing techniques are applied to identify the bearing defect, including signal pre-whitening, gear/bearing signal separation, kurtogram, envelope analysis, high-order spectral analysis and so on. The comparative results suggest that certain combinations of aforementioned methods are more effective than single process techniques. One case of successful detection is demonstrated in this paper. This study potentially benefits improving HUMS effectiveness and supports helicopter maintenance decision-making.

Recently, anti-fingerprint surfaces have attracted wide attention due to their self-clean and esthetic performances. The surface texture is a determinant parameter that governs such properties. In this paper, the anti-fingerprint function of microstructured surfaces has been investigated. We have studied the effect of some topographic parameters on the mechanical behavior of the finger contact. Our analysis is mainly focused on the effect of the pitch value and the aspect ratio of the surface patterns on the anti-fingerprint function. A numerical approach has been employed to model dry contacts between the human fingertip and differently microstructured surfaces. The fingertip was modeled taking into account the topography of the finger skin (finger ridges) and the mechanical properties of the finger tissues. Results indicate that the pitch value has a critical effect on the anti-fingerprint function particularly for low aspect ratio surfaces. This highlights the relevance of the texture properties on the surface functionality.

Road profile estimation has become an indispensable tool for improved route planning and enhanced design of active suspensions. Performances requirements, such as increasing ride comfort and improving the driving maneuverability, depend on the road unevenness. The core idea is to use vehicle dynamics to get information about road perturbation and isolates passengers from vibrations. Online estimation of geometric variation of the road was investigated in this paper based on the operational calculus method and algebraic approach. The estimator equations are derived from a predictor scheme which was used to approximate this unknown signal variation by a piecewise constant function. The major interest of this technique is that it allows using minimum numbers of mechanical sensors and few parameters for tuning. Accurate approximations were obtained from the measurement of sprung mass and un-sprung mass vertical displacements. Numerical results with MATLAB/Simulink environment were used for investigating the effectiveness of the proposed technique for fast prediction.

This article deals with the method of cathodic protection by imposed current. This technique reduces the rate of corrosion of a metallic material in the presence of an aqueous medium. Corrosion, its causes, its effects as well as the solution to combat this phenomenon, has been established in this paper. Indeed, the technique of protection by imposed current has been studied extensively in this work. The study and installation of a cathodic protection system imposed on-board the vedette, it is possible to determine the need for a DC current. This study ensures a good protection of the hull and a better location of the anodes. An imposed current regulation system has been studied. This system consists of measuring the potential of the boat’s hull by the reference electrode. With reference to this voltage value, the controller imposes the necessary current injected at the anode to maintain a fixed protection potential. In order to validate this study, simulations results under PSIM software dealing with protection of the hull of the vedette is finally presented.

Drivetrain vibrations are a great concern in the automotive industry, once they are related to many Noise, Vibration and Harshness (NVH) phenomena. An automobile drivetrain system generally consists of the following main components: engine, clutch, gearbox, disk brake, and transmission shafts. This paper represents a nonlinear dynamic model for each drivetrain components in the presence of the acyclism phenomena (cyclostationary regim). This model is simulated by 18 degrees of freedom. The governing nonlinear time-varying motion equation formulated is resolved by the analytic Runge–Kutta method. The dynamic responses of the clutch and the single-stage helical gear reducer are investigated in the idle engine regime. The results are presented in the time and time-frequency domain by using the Wigner-Ville distribution. The dynamic behavior study of the system, comes to confirm the significant influence of the engine excitation (torque and speed fluctuation), particularly in the case of the gasoline engine acyclism condition.

The conversion of the Direct Normal solar Irradiance (DNI) energy into thermal or electrical energy is performed by concentrating solar power systems. They use the received solar radiation to expose an industrial working fluid to high temperature. A good knowledge of the availability of the DNI in the place of settlements of a solar power plant plays a crucial role in the design of solar collectors and the optimization of operations within the industrial applications. In regions where no solar radiation measurements are available, the modeling of the DNI is commonly adopted to determine the solar radiation potential of the site. However, the DNI models could predict the direct solar radiation with high uncertainty. This paper presents a performance analysis of three DNI clear sky models: Ineichen, Iqbal, and Solis models to predict the Direct Normal Irradiance. The performance analysis conducted in our study consisted of validation and calibration of these models using 10 min resolution measurements performed in a southern Tunisian region (Tataouine). The purpose of our research is to improve the accuracy of the DNI model prediction and to offer more reliable estimations. The results of the sub-hourly statistical validation of these models show that the Iqbal model achieves the lowest uncertainty of prediction. After performing calibration with the in situ measurements, The results show that, the uncertainty of estimation, represented by the relative root mean square error (rmse%), has been generally reduced by 3%. For a high DNI intensity, the lowest errors are recorded by the corrected Solis model (rmse% = 6.2%) while, for a low DNI intensity, it reaches 25.6% which is recorded by the corrected Iqbal model.

High-density polyethylene (HDPE) is one of the most widely used materials in fluid transport networks due to its good resistance to wear and corrosion, ease of installation, and low cost. However, HDPE is a flexible material and therefore more vulnerable to scratches and other types of damage during transport and installation. Therefore, accurate prediction of crack initiation pressure in damaged pipes is a very important point in the safety analysis of HDPE piping systems. In this study, a new semi-empirical formulae, which predicts this critical pressure, is developed. The cracking pressure depends on the mechanical characteristics of the material and the geometric parameters (pipe geometry and defect size). A parametric study based on numerical simulations was established in order to quantify the influence of each parameter on the cracking pressure. The pressures calculated by the proposed formulae in a HDPE pipe having a superficial defect are in good agreement with the burst pressure determined experimentally for the same geometry.

A better understanding of coating is required to increase productivity and tool life in especially dry cutting conditions of difficult to cut materials. In this work, in order to evaluate the performance of coated TiAlN cutting tool during orthogonal cutting of Titanium Ti6Al4V alloys, a 2D finite element modeling using the commercial code ABAQUS/Explicit is developed. Lagrangian approach has been adopted. Different cutting conditions have been defined, cutting tool geometry (coated TiAlN et uncoated tool) has been changed in the order to validate numerical model results. An acceptable correlation between numerical results and those of the literature is obtained in terms of chip morphology, cutting forces, feed forces, and temperature distribution. Numerical results have highlighted the effect of coated TiAlN tool on temperature distribution at tool-chip-workpiece interfaces, on chip morphology and its geometry, as well as cutting and feed forces. We can conclude that the FEM employed in this study gives significant information about tool coating effects on machining difficult to cut materials.

In this present work, we have studied the directed co-flow effects on mean and turbulent flow properties of a turbulent heated plane jet with variable density discharging into a directed co-flowing stream. The first order k-εturbulence model is applied and has been compared with the existing experimental data. The Finite Volume Method (FVM) is used to discretize governing equations. First of all, it is found that predicted results are in satisfactory agreement with the experimental findings. Moreover, the numerical results of the mean and turbulent quantities has been presented and discussed in this work. The major interest of presenting this model is that to show the importance of the directed co-flow with a positive angle, which is enhancing the mixing. Furthermore, a qualitative analysis of the air entrainment would suggest that the higher inlet hot air jet temperature affect more the lateral in flow of air into the jet and jet lateral expansion is augmented when the inlet hot air jet temperature increases. Therefore, the increase of the inlet hot air jet temperature decreases faster the axial mean velocity and thus more entrainment air is required.

Due to the lack of studies that investigate the transient behavior of centrifugal pumps during starting and stopping periods, this paper provides a numerical study to predict the variation of the dynamic behavior of the flow during the starting period of a centrifugal pump by considering an actual motor torque. The numerical study is based on the characteristic method of specified time intervals taking the pressure head and the flow rate as two dependent variables. After developing the continuity and motion equations, a study based on the pump motor equation was carried out in order to determine the impeller angular velocity variation during the starting time. The numerical obtained results have shown that the pressure increase is more important in the case of a relatively short starting time compared to a long one. These results have shown a good agreement with those obtained by experiment. In this study, the influence of the impeller geometry on the pressure head and flow rate is also investigated. The obtained results have shown a dependency of the pump dynamic behavior with the impeller geometry during the starting periods.

Centrifugal pump is a major cause of pressure perturbations in hydraulic installations. The internal geometry of this turbomachine and its running conditions affect excessively the magnitude of these excitations. In the present study, a numerical investigation is conducted to analyze the influence of the volute diffuser type on flow characteristics in centrifugal pumps with the same impeller under wide range of flow rate. An unsteady numerical analysis was carried out in order to study the strong interaction between blade and tongue with two different geometries of the volute. The main objective is to analyze the characteristics of pressure and force fluctuations inside the pump. For tangential diffuser shape, the pressure fluctuation amplitudes are greater than that in the case of a radial diffuser. Based on the fast Fourier transform (FFT), the spectral analysis was performed on the pressure fluctuation signals in frequency domain under running condition for two volute at different monitoring points in the pump. The time frequency characteristics of these pressure fluctuations were affected greatly by both volute type and measurement locations in each diffuser. However, simulation results were compared with the available experimental data, and an acceptable agreement was obtained. The results obtained in this work can provide a useful reference for designing the type of volute diffuser in pump.

Facility Layout Problem (FLP) is concerned to arrange facilities efficiently within the available floor area in order to operate in an efficient way. So, the aim of this paper is to provide a survey related to the criteria that affect the effectiveness of a facility layout. The design criteria can be classified according to the previous research into two categories which are qualitative and quantitative indicators. Then, this paper presents a review of different Multi-Criteria Decision-Making (MCDM) techniques that have been proposed in the literature to pick the most suitable layout design. These methods are particularly suitable to deal with complex situations, including various criteria and conflicting goals which need to be optimized simultaneously. The review serves as a guide to those interested in how to evaluate and select the most appropriate layout which can handle an expanded range of manufacturing companies. Finally, we present a discussion followed by a conclusion.

This study examines the role of both a radial flow created at the entrance of the die and the average molecular weight of polymer, on the appearance and development of the sharkskin defect. To do so, three linear polydimethylsiloxanes (PDMS) of different viscosities and molecular weights were considered. A convergent radial flow was created at the entrance zone by imposing a rod upstream the die. It was found, that when the radial flow is well established in the entrance zone (i.e., for very low gaps between the bottom of the rod and the plane of the die) the onset of sharkskin defect can be translated to higher flow rate. As the influence of molecular weight of polymer, it was shown that the extrusion of lower molecular weight PDMS can delay the occurrence of sharkskin instability. Besides, it was remarked that the morphology of the extrudate associated to the trigger of surface defect is not affected with the presence of radial flow in the entrance region or with the molecular weight of the extruded polymer.

The aim of this work is to experimentally investigate the effect of the cooling/heating rate on both entropy and enthalpy changes during the phase transformation of the Ni-rich NiTi Shape Memory Alloy (SMA). The thermal analysis was performed at zero stress using the Differential Scanning Calorimetry (DSC) technique. From the obtained calorimetric results, it was found that the transformation temperatures are considerably sensitive to the cooling/heating rate variation, mainly the finish temperature of the forward martensitic transformation (M_f). Accordingly, it was shown that enthalpy and entropy changes, during the phase transformation process, are strongly affected by the change of this parameter. Based on Gibbs fundamental equation, the evolution of the Gibbs free energy change was also discussed. The findings of this study can be useful to predict the evolution of the critical stress–temperature diagram. Indeed, the enthalpy change describes the evolution of the diagram slopes as function of the cooling/heating rate which allows to limit each occurred transformation domain and defines the material mechanical behavior whether superelasticity or shape memory.

In this paper, the relationship between the heat treatment temperature and the phase transformation behavior in the Ni-rich NiTi Shape Memory Alloy (SMA) was experimentally investigated. The characterization of the thermoelastic martensitic transformation at zero stress was performed based on differential scanning calorimetry (DSC) experiments. It was shown that the R phase behavior is extremely affected by the increase of the heat treatment temperature. For the samples heat treated below 650 °C, the R phase appears in both forward and reverse transformations. However, it completely disappears above this heat treatment temperature. Moreover, it was reported that the NiTi thermal behavior and mainly the transformation temperatures are strongly influenced by the heat treatment temperature change. By increasing this parameter, the austenitic finish temperature (A_f) is considerably decreased while the martensitic one (M_f) is increased which greatly affects the thermal transformation hysteresis. Accordingly, the effect of the this thermal behavior on the NiTi diagram phase was discussed. The obtained findings were largely in line with previously published studies.

Sewing is one of the most commonly used manufacturing processes in the world. In the textile industry, development of sewing machines with optimal performances has found a great attention during recent years. Therefore, this work deals with the multiobjective design optimization of a sewing machine viewed as a mechatronic system. The mechatronic model of the machine is developed based on the coupling of the needle-bar-and-thread-take-up-lever (NBTTL) dynamic model and the DC motor model. Based on the mechatronic model, the DC motor current and its fluctuation are minimized, simultaneously, in order to minimize the load on the motor and the machine vibration. The multiobjective imperialist competitive algorithm (MOICA) is used to solve this problem. The obtained results are presented as a Pareto front, since the two objective functions are shown to be contradictory. Out of the solutions presented in the Pareto front, the designer can choose the one with the best compromise for his application.

The present study introduces a numerical model for one of the most important fluid–fluid interaction problems in industrial engineering applications, mainly a gas jet impinging perpendicularly onto a liquid interface. A better understanding of the process of the interaction of this type of flow was performed using the Reynolds Stress Model (RSM). The Volume Of Fluid (VOF) method is employed to follow the deformation of the liquid surface. The results from the numerical tests are comparable with those presented by Muñoz (Appl Math Model 36:2687-2700, 2012) and it is found that computational results agreed well with experimental data. The obtained numerical results provide useful insight and a better understanding of the highly complex flow encountered in such processes. Moreover, we propose to examine the effect of the nature of the liquid on the development of the global flow. Dynamic characters of liquid surface such as the presence of the cavity and the formation of the wave were displayed.

The simulation of natural gas transmission pipelines has been studied by many workers. To simulate one-dimensional transient flow in natural gas pipeline, the continuity and momentum equations must be solved simultaneously. This creates a set of nonlinear partial differential equations, which are complex and cumbersome. The numerical solution, by the method of characteristics of the general equations governing the transient state, is then developed by introducing an inertial factor. A computer programme was developed to study the transient flow in a system of pipelines with a constant pressure upstream and imposed downstream consumption.

Due to their eco-friendly, bio-degradability characteristics and good mechanical properties, natural fibre composite has become a good alternative in many composite applications such as automotive, aerospace and furniture construction. The present study deals with the mechanical properties of flax fibre reinforcement associated to Elium which is a thermoplastic resin. First, the composite prepared by liquid infusion was subjected to quasi-static tensile loading and cyclic tensile test to investigate macroscopic damage behaviour. Second, a three-point static and fatigue bending test were performed to failure. In case of fatigue test, the hysteresis loops was used as a measure for stiffness degradation, energy dissipation and loss factor. Many configuration of laminate were prepared for experimental work. The flax/Elium composite has shown a promising solution that could be integrated in many industrial applications thanks to its short time needed for manufacturing by infusion and its good mechanical characteristics.

In order to accurately estimate the temperature reached in the cylinder block and cylinder head gasket of an internal combustion engine, an experimental investigation of the thermal contact resistance (TCR) across cylinder head gasket is performed. TCR has been calculated for contact pressure up to 42 MPa which corresponds to the clamping pressure of the gasket. Different sections (inter-cylinders, oil, and water ribs) with different law behavior have been retained. The temperature evolution has been recorded using thermocouples immerged in the measurement device. The heat flux has been calculated using this temperature evolution. The TCR has been deduced using Fourier law. Results show that the TCR decreases with increasing the load and tends toward a constant value for various sections of the gasket. In addition, TCR values are more important for the inter-cylinder’s section which will result in greater values of temperature near inter-cylinder’s section on the cylinder block.

In this paper, a dynamic study is carried out for a new laminated glass plate which contains two elastic skins, a viscoelastic core and two adhesives films supposed to be ultra-thin layers; and which can be used for the assembly of the laminated structure. In this case, the coupling between all layers is modelled by taking into account the interfacial shear stresses. Hence, by mixing the Kirchhoff and Mindlin plate’s theories respectively for the two skins and the viscoelastic core with a dynamic behaviour rule for the two ultra-thin films, the displacement field in the laminate can be derived. Here, the finite element method is used for discretizing the laminate energy functional allow obtaining a complex dynamic equation. Also, the dynamic modal recombination method is adopted for calculating the vibratory responses of the studied structure. Then, the aim of this work is to determine the effect of the interfacial shear stress on the dynamic behaviour of the laminated plate.

At present, Computer-Aided tools are at the heart of the product development cycle. These tools can accelerate and make more efficient the design and simulation tasks. However, there is no commercial aid tool for the assistance in the assembly/disassembly tasks. In this context, many approaches and methods are proposed in which feasible assembly/disassembly sequences can be generated. Amongst the limitations of those approaches is the considerable processing time. In this paper, we propose an approach for the simplification of the product CAD model in order to generate Assembly Sequences (AS). The developed approach, which is automatic and integrated to CAD system, begins by the identification and the elimination of standard components (such as screws, nuts, keys, etc.) present in the model. Then a simplified AS is carried out using a collision analysis. Finally, the global AS is obtained by inserting the eliminated elements into the final AS using a case-based algorithm which contains a census of the different standard component types. This developed case-based algorithm allows, according to the type, the identification of the assembly direction and the chronological order of the eliminated standard component.

Masonry wall is a composite structure formed by units linked vertically and horizontally by mortar. One of the interests in this paper is composed of hollow concrete blocks. Generally, in structural analysis of masonry wall, the determination of the limit strength presents a challenge, due to the complexity and the heterogeneity of his constituent materials. In the present paper, a numerical homogenization is used for the estimation of the strength domain of an in-plane loaded masonry by accounting for the failure of its blocks. The determination of this domain was based on a rigorous definition of the microstructure in three-dimensions, on convex analysis and on the kinematical approach in the frame of limit analysis theory. A three- dimensional periodic basic cell with a nonlinear material behavior is used. Periodic boundary conditions have been imposed on the lateral boundary of the unit cell by matching the degrees of freedom of pairs of nodes.

The quick environment development make impossible that an enterprise, working individually, can respond to market opportunities. For this reason, more and more firms are aware and motivated to improve their offer and competitiveness by means of collaboration, through sharing competencies and resources. Thus, the purpose of this paper is to describe, through a literature review, the key concepts related to a Collaborative Network (CN) and to provide a classification of networks. Furthermore, the key issue of the CN is the selection of the right partners, which is performed based on several, sometimes conflicting, quantitative, and qualitative criteria. Thus, this task is considered, in the literature, as a Multi Criteria Decision Making (MCDM) problem. Therefore, the second objective of this research is to survey this area by identifying the frequently used criteria, in strategic and tactical management level, as well as the MCDM approaches.

Nowadays, global speedy transformations have required the company to investigate on risk supply chain management. The goal of this investigation is to overcome their around insecure conditions. The objective of this paper is to present supply chain risk management area. In this context, we propose a conceptual framework of the supply chain risk management process. This process involves basically four sequential steps: identification of risk, analyzing of risk, evaluate of risk, and control and monitoring of risk. Further, we recap the different sets of risk and we present the frequent techniques that used to measure risk in the literature review of supply chain risk management. After that, we synthesize some works based on the approach of resolution. Finally, analyzes and potential areas for future research will be presented. This paper contributes to current risk management literature by providing an efficient gait to manage risk which makes company to mitigate the negative effect of risk.

The wind turbine blade segmentation development remains a tough challenge for constructors to reduce the blade manufacturing and transport cost. In this paper, numerical analysis is developed in order to study the dynamic characteristics of a segmented wind turbine blade assembled with a spar. The spar and the blade segments are assimilated to a shell structure with different homogeneous and isotropic materials. Accordingly, the three nodes triangular shell element DKT18 is adopted to model the blade. To reduce the problem size the Craig–Bampton substructure method is applied. This study covers the effects the of twist angle on the blade natural frequencies. To validate the accuracy and reliability of the proposed substructuring approach, numerical results obtained from the present study were compared with those determined by modal analysis using ABAQUS software. Results showed that the blade natural frequencies are not monotonically varying with respect to the twist angle which must be investigated to be well above the wind turbine system frequencies.

Today, the environmental problems become serious and they are highlighted in regulations frameworks. Then, the use of Life cycle assessment (LCA) tools, for assessing products environmental impacts, is necessary, till Computer Aided Design (CAD) phase, for manufactures aiming at guarding their market places. Required LCA data (processes) can be provided from CAD and Product Life Management integrated systems (CAD/PLM), which became a necessity for industries to manage easily their data. In this paper, we propose a new CAD data model oriented ecodesign which we name “Eco-feature”, based on the exploration of CAD/LCA systems to extract possible features life cycle scenarios, in order to select the most ecological one. Hence, firstly, we present the state of the art of researches aiming at connecting CAD/PLM systems to LCA tools. Secondly we present our new approach and describe its advantages. Finally, we present a case study to valid the new proposed concept.

This paper covers the study of the effect of surface topography on tribological behavior in the early stage of repetitive sliding under dry condition. Reciprocating sliding tests were conducted on AA5083 sample against smooth AISI52100 ball bearing. Unidirectional polishing was adopted for the surface preparation of AA5083 samples. Experiments were performed at a pressure of 200 MPa for a maximum number of 1000 cycles. The sliding velocity and the sliding track were kept constant at 50 mm/s and 15 mm, respectively. Evolution of friction coefficient as a function of the sliding distance was monitored. Wear was characterized using scanning electron microscope (SEM), energy-dispersive X-ray spectroscope (EDS), and profilometer. Experimental results have shown that the friction coefficient as well as wear mechanisms, significantly, depends on the initial surface topography. Particular focus was put in the study of the effect of the mean absolute profile slope $$\Delta_{a}$$. Results showed that the mean absolute profile slope $$\Delta_{a}$$ played a major role in friction and wear.

Nowadays, mechanical products which respond to customer requirements become more and more complex. Concurrent engineering environment requires that various computer-aided tools be used concurrently for design, analysis, and validation of complex product. Computer-aided design (CAD) and computer-aided engineering (CAE) tools should have the capacity of integration or easy interoperability. However, many of them are often unconnected systems that are not intended for collaborative use. Engineering designers and analysts tend to use specific CAD software for design and other CAE software for analysis. Consequently, the triplet (Cost/Delay/Quality) of a complex product cannot be improved. In this paper, a disassembly plan (DP) generation based on a coupling between Solidworks and Matlab is detailed. Base on an encapsulation of parts into a subassemblies bloc, the proposed approach aims to automatically integrate the both softwares in a concurrent engineering context in order to identify and generate a feasible and optimal DP. A comparative example is presented in order to highlight the feasibility and efficiency of the proposed approach.

The disposal of effluents in nature and more particularly in the sea is a very frequent practice. The discharge of wastewater into a receiving environment such as seawater is generally in the form of a turbulent jet. The efficiency of the dispersion of the jet depends on its characteristics of mixing with the ambient environment and when the latter is in motion, it is significantly modified. This paper investigates a numerical study about buoyant wall turbulent jet in co-flow stream. A light fluid of freshwater is injected horizontally and tangentially to a plane wall into homogenous moving environment of saltwater. Since the domain temperature is assumed to be constant, the density of the mixture is a function of the salt concentration only. The mathematical model is based on the finite volume method and reports on an application of standard turbulence model k-ε for steady flow with densimetric Froude number of 11 and Reynolds number of 3800. The aim of this work is to predict the influence of the co-flow stream on the dispersion of the jet and the mixing processes between freshwater jet and ambient saltwater. The concentration contours, the cling length, and the central trajectory of the jet are determined. It is found that the jet behavior depends on the co-flow-to-jet velocity ratio.

Drug shortages are the most complex and critical existing problems in public hospitals; this is due to different causes like deficiencies in the supply chain of medicines and parallel trade. This problem is costly for hospitals because it can affect patient’s safety. For this, hospitals have to find solutions to protect their patients and to provide drugs in the right amount at the right time. Among solutions, which help to resolve these problems, there is the collaborative supply chain. Collaborative supply chain is-based on the interaction and collaboration between organizations in order to achieve a common goal and obtain mutual benefit. This study extends research to show the impact of collaboration between hospitals on reducing the drug shortages problem. In addition, we will investigate the importance of collaboration within horizontal supply chain, by presenting different strategies, such as placing orders in different dates, standardization of orders dates and group purchasing organization and seeing the impact of each strategy on solving the drug shortages in Tunisian healthcare sector.

We report activation volume measurements of Zr-based Bulk Metallic Glasses (BMGs) through nanoindentation tests. Monotonic and cyclic nanoindentation loadings are carried out at rates ranging from 250 to 2500 µN/s and at ambient temperature. The quantitative analysis of the activation volume parameter is determined using depth variation at constant load. In particular, the effect of loading rates on the activation volume of metallic glass is studied. Under quasi-static cyclic loading, series of measurement revealed that activation volume depending on the number of cycles and the loading rates. Indeed, a significant increase in the order of 96% of activation volume at 250 µN/s is determined. Furthermore, a quantitative analysis in terms of the plastic yield criterion for improving the identification of the shear band initiation key parameter in the BMGs is developed. Both the Von Mises and Mohr Coulomb constitutive description of plastic yield criterion were used in the calculation of the activation volume parameter. The numerical results based on Mohr Coulomb criterion are three to four times higher than the Von Mises criterion.

In order to achieve more realistic structural parameter identification, it is inevitable to account for uncertainties. The present paper proposes a stochastic identification process to identify propagation parameters such as the wavenumber, the damping loss factor, and the wave attenuation, in presence of uncertainties. The proposed stochastic identification process combines, in a wave propagation framework, the Inhomogeneous Wave Correlation method with the Latin Hypercube Sampling method. It is compared to the identification process combining the Mc Daniel method and the Latin Hypercube Sampling method which are considered as reference for structural identification and uncertainty propagation, respectively. An isotropic beam example is considered and identification is done from Frequency Response Functions computed at several measurement points which coordinates are supposed to be the uncertain parameters. The effects of uncertainties on parameter identification are evaluated through statistical quantifications of the variability of the identified parameters. Obtained results show that all identified parameters are affected by uncertainties, except damping.

The single point incremental forming process is an emerging process which presents an alternative to the conventional sheet-metal forming processes like stamping and drawing. It is particularly suitable for prototyping and low production thanks to its flexibility and low cost. The objective of this paper is to study the incremental forming of titanium grade2 and AISI 304L stainless steel sheets. The forming force of sheet titanium grade2 and 304L steel parts formed by single point incremental process depends on different parameters (tool path, tool size, materials and shape, friction, etc.). During the process, considerable forces can occur which must be controlled to ensure the safe use of the CNC milling machine. The aim of this paper is to study the effect of different process parameters on the maximal force. Experimental and numerical studies are performed. An optimization method based on the use of an experimental design and response surface method is used to minimize the forming force.

In case of complex processes, the identification of out-of-control states, observed on control charts, and their specific assignable causes are very complicated tasks. To overcome these difficulties artificial intelligence techniques have been used. Among these methods, the artificial neural networks can develop intelligence by using process data without need to expert opinion. This paper proposes an original method for process monitoring based on control chart exploration using artificial neural networks applicable for high batch size production requiring high sampling frequency. The developed approach helps to identify the out-of-control states and the corresponding process defects that lead to their occurrences. Attention is given to three most frequently observed cases in industrial practices: shifts, ascending and descending trends, and cyclic phenomena. The developed neural networks use back propagation algorithm and one hidden layer. A real industrial case of study was used to evaluate the recognition and identification performances of the developed artificial neural networks. Results have shown excellent recognition rates that reached percentages of identification of both process deviations and assignable causes higher than 90%.

For better surface quality and production efficiency in mechanical manufacturing, operators need to make a good choice of cutting parameters such as depth of cut, cutting speed, feed rate and also the cooling condition that affects not only product quality, but also respects the ecological aspect and preserves environment. In the current work, an experimental study has been carried out in order to evaluate the influence of cutting parameters on surface roughness, when turning of X210CR12 steel using multilayer-coated carbide insert with various nose radius. The ANOVA analysis has been performed to determine the effect of cutting conditions on Ra. The results have been analyzed using S/N ratios, mean effect graphs, and 3D response surface plots. The results indicate that the cutting insert nose radius and the feed rate are the mainly affecting factors on surface roughness. Confirmatory experiments have been established after Taguchi’s optimization. It has been found that the MQL is an interesting way to minimize lubricant quantity, protect operator health and environment with keeping better machining quality.

The growing demand for more fuel-efficient vehicles to reduce energy consumption and air pollution is a challenge for the automotive industry. The aluminium alloy can replace steels and copper in this industry. In this framework, we are interested in studying the behaviour at high strain rate. Dynamic tensile tests are conducted on aluminium alloy (AA) 6063 using a split-Hopkinson tension bar and a sensing block system to validate the testing technique and to investigate the strain-rate effect on the material’s stress–strain behaviour and failure mode. We present the experimental procedures and results discussing the constitutive response of the alloy at strain rates up to approximately 1500 s−1. We tested two different specimen sizes at a wide range of actuator velocities to achieve the desired strain rates. Results show that the yield strength, ultimate strength and failure strain were dependent on strain rate. We fitted the data to the Johnson-Cook (JC) constitutive model and the resulting parameters are comparable to published results in similar work.

The mechanical behaviour of the pipe wall material plays a major role in determining the pressure response of a fluid system during transient events. In regards to the behaviour of plastic pipes, such pipes have been widely used in water supply networks. This paper investigates and compares, numerically, the pressure response of a polyethylene high density (HDPE) pipe and a rigid steel pipe in case of exposure to transient events. The governing equations of the system are two coupled nonlinear hyperbolic partial differential equations, continuity, and momentum. The classical water hammer theory was used in the numerical modelling. The initiation of the hydraulic transients in the network was caused by a sudden centrifugal pump failure. The numerical resolution of the pressure-discharge equations is performed using the method of characteristics. The pressure fluctuations in polyethylene pipelines were found to be delayed in time compared to rigid pipes. The delayed wave celerity in polymeric pipeline is an asset for damping transient waves over time.

The selection of a suitable technique for manufacturing of a specific product represents a complex issue, especially for the biomedical field. Single point incremental forming (SPIF) process presented an alternative manufacturing means in producing biomedical parts characterized by the need of patient-specific geometry. In addition, the titanium alloy Ti–6Al–4V is one of the most frequently used materials for biomedical application. Due to its poor-room-temperature formability, deformation under high temperature is needed. In this context, the present work aims at proving the feasibility of the hot incremental forming of titanium alloy Ti–6Al–4V denture base by finite element simulations. The effects of the forming temperature on the material failure and more particularly on the geometric accuracy of the final product were investigated. The comparison between the final deformed geometry predicted numerically and the target one obtained from CAD modeling is conducted. Therefore, a good agreement has been obtained and significant improvements in terms of geometric accuracy have been reached employing the SPIF at elevated forming temperature.

In this paper, we propose a new approach for taking into account uncertainties based on the projection on polynomial chaos method. The new approach is used to determine the dynamic response of a one-stage spur gear system modeled by eight degrees of freedom in the presence of friction coefficient between teeth that admits some dispersion. Therefore, it becomes necessary to take this uncertainty into account in the stability analysis of gear system to ensure robust predictions of stable and instable behaviors. The simulation results are obtained by the polynomial chaos approach for the dynamic analysis of a one-stage spur gear system with the uncertainty associated with friction coefficient on the teeth contact. The proposed approach is an efficient probabilistic tool for uncertainty propagation. The polynomial chaos results are compared with Monte Carlo simulations. The main results of the present study show that the polynomial chaos may be an efficient tool to take into account the dispersions of the friction coefficient of a one-stage spur gear system.

In this paper, a multi-item capacitated lot-sizing problem (MI-CLSP) with backlogging is considered. The problem is formulated as bi-objective optimization model with two conflicting objectives. The first one aims to minimize the total cost composed of production, setup, and backlogging costs and the second one aims to minimize the total inventory level. Augmented epsilon-constraint method is adopted when solving this problem in order to find the set of Pareto-optimal solutions. The goal of this study is to investigate the effect of variation in the backlogging cost on optimal Pareto solutions of the MI-CLSP. Several numerical examples with different demand typology are tested. The different sensitivity analyses show a considerable effect of the variation in the backlogging cost on the set of Pareto-optimal solutions. This investigation offers to the decision-makers a global visibility on the influence of variation on the backlogging cost on the optimal solutions of a MI-CLSP.

The present work aims to investigate the influence of flow geometry on volume instability associated to a linear polydimethylsiloxane (PDMS). To do so, a convergent radial flow is created at the die entrance. Particle Image Velocimetry (PIV) recordings performed under unstable flow regime, in the capillary rheometer, characterized with the new entrance zone, show a new pattern of streamlines above the die: elongational stresses are less pronounced; furthermore elongational stresses, as well as shear stresses, tend to concentrate near the lip of the capillary die. Photographs of extrudate strands obtained at the die exit, depict a new morphology of defect which appears with a well-established radial flow. These results lead to the agreement the correlation between the gross melt fracture and the flow instability at the entrance zone, as well as the importance of elongational and shear components linked to the upstream flow in the appearance and the development of volume distortion.

In this paper, the tribological behavior of the high-density polyethylene(HDPE) against the M30NW stainless steel was studied. A reciprocating pin-disk tribometer was used to conduct wear tests under dry and lubricated conditions. Two lubricants were used including saline solution (NaCl 0.9%) and nigella sativa oil. The disulfide of molybdenum (MoS₂) was used as an additive to the retained lubricants. The coefficient of friction and the wear volume measured on HDPE were studied. The morphological characterization of the polymer disks and metallic pins was carried out. It is found that the use of the saline solution and nigella sativa oil as lubricants increases the tribological performance of M30NW/HDPE pair. The addition of 2 wt% of MoS₂ to both lubricants does not show a significant decrease of the wear volume of HDPE comparatively to dry conditions. The performance of the nigella sativa oil was related to its adsorption ability to the stainless steel surface. The mechanism of nigella sativa oil adsorption on the M30NW surface is presented and discussed.

The effect of disorder on the collective dynamics of two coupled nonlinear pendulums is investigated in this paper. The disorder is introduced by slightly perturbing the length of some pendulums in the nearly periodic structure. A generic discrete analytical model combining the multiple scales method and a standing-wave decomposition is proposed and adapted to the presence of disorder. The proposed model leads to a set of coupled complex algebraic equations which are written according to the number and positions of disorder in the structure. The impact of the disorder on the collective dynamics of two coupled pendulums structure is analyzed through the frequency responses and the basins of attraction. Results show that, in presence of disorder, the multimode solutions are enhanced and the multistability domain is wider. The disorder introduced by reducing the length of one pendulum favors modal localization on its response. In practice, the energy localization generated by disorder is suitable for several engineering applications such as vibration energy harvesting.

Vibrations, considered one of the major problems in the engineering applications, are analyzed to predict their detrimental effects on the equipment and structures. The metal mesh isolator, named also metal rubber, has become widely applied to mitigate the disturbing vibration due to its special production techniques. Metal rubber is a kind of novel style porous damping material that is manufactured via a process of wire-drawing, weaving and compression moulding. This paper investigates the influence on the compression and dissipative behaviour of the metal mesh isolator provided by the relative density. The mechanical properties of five metal mesh samples with cylindrical geometry and with different relative density are obtained from a quasi-static cyclic compression test. The loading-unloading results of the five samples, subjected to a constant compression level, show the strong dependence exerted by the relative density over the compressive properties. Experimental analysis indicated that the porosity affects the stiffness but has an opposite effect regarding the loss factor. By increasing the ratio between the isolator’s and wire’s densities, the nominal stiffness increases, but the reduction of loss factor is obvious.

The objective of this work is to provide an operational model for the numerical simulation of the shaping processes by plastic deformation of thin plates made of Titanium alloy. Hence, the importance of developing a general framework of elastoplastic orthotropic models (initial orthotropy and isotropic hardening) based on the choice of an equivalent stress, a law of hardening for the development of a strategy of identification of the model from an experimental database. At this level, the identification of the constitutive parameters involved in the laws of behavior of the materials represents an important step in this work. A new identification strategy accompanied by its validation using the criterion of Barlat will be proposed. Numerical simulation can be a very useful tool for titanium alloy. Mainly due to its use in orthopedic surgery; Titanium is of great interest because of its elasticity modulus very close to that of the bone.

Estimation of individual muscle forces during human movement can provide insight into neural control and tissue loading and can thus contribute to improved diagnosis and management of both neurological and orthopaedic conditions. Direct measurement of muscle forces is generally not feasible in a clinical setting, and non-invasive methods based on musculoskeletal modeling should, therefore, be considered. The current state of the art in clinical movement analysis is that resultant joint torques can be reliably estimated from motion data and external forces (inverse dynamic analysis). The purpose of this paper consists in developing and simulating a biomechanical model of the lower limb, more precisely, of the foot during its movement. In this paper, we are interested in the calculation of the ankle joint. First, we have studied the muscular length variation as a function of the variation of the flexion angle. Then, we focus on the determination of the muscular force produced by muscles and involved in the flexion movement and the foot extension. Finally, we have cited the findings and the interpretations appropriate to the results obtained.

In this paper, we study the air cooling of circuit boards populated with multiple integrated circuits using natural convection. The simulation and the modeling results of the model are obtained by digital software Comsol Multiphysics. The results then accurately describe the heat transport and temperature changes. From such simulations, it is also possible to derive accurate estimations of the film coefficients. The objective is to determine the evolution of the temperature and the flow of the velocity of the fluid. The results show that the temperature of the ICs (the heat sources) increases considerably under a constant heating load from the components. The temperature increase of the sources varies from 30 K for the lowest IC up to 90 K at the top IC. For the velocity of the fluid, the circuit board contributes a large amount of cooling power on its backside, although the thermal conductivity is quite small.

This work investigates the effect of gravity of carrier on the dynamic behavior of back to back planetary gears in a stationary condition. A tridimensional lumped parameter model is developed in order to study this phenomenon. The gravity of carriers has an effect on the distance between gears and it is included in the model through sun-planets and ring-planets mesh stiffness which influence on the dynamic response of gear. Numerical results are correlated with the experimental results obtained from a back-to-back planetary gear test bench, this test bench is composed of two identical planetary gears sets: reaction gear, where the ring is free and test gear where the ring is fixed. They are connected through two rigid shafts. A fix external load was applied through an arm attached to the free reaction ring. Data Acquisition System acquired signals from accelerometers mounted on the carrier and the ring. The signal processing was achieved using LMS Test.Lab software.

This paper deals with the prediction of the 3-UPU translational parallel manipulator position error caused by the design parameter uncertainties. An algorithm, based on the interval analysis is developed and used to estimate the distribution of the position error within the robot workspace. As a result, we represented the distribution of the position error in different sections of the workspace and we showed that the minimum of the position error is located in the neighborhoods of base center. In general, the minimum position error is reached for higher sections of the workspace. Moreover, the effect of each design parameter uncertainty on the manipulator precision at different sections of the workspace is discussed. At the extreme points of the workspace, the most influent design parameters on the position error are the leg position angles and the radius of the base and the platform uncertainties. The actuator lengths uncertainties are supposed constant and have no effect on the platform position error.

This work was aimed at investigating the influence of stress concentration factor on the evolution of the strain energy release rate J in 5-harness satin weave carbon fabrics reinforced Polyphenylene sulphide (PPS) structures at 120 °C (higher than the transition temperature T_g). The studied angle-ply (AP) laminates are characterized by a highly ductile behavior. For this purpose, the load separation method, as well as the compliance method, are applied in order to determine the strain energy release rate J for different crack length over specimen width ratios a/W. A fractographic analysis was conducted to understand the chronology of damage mechanisms which significantly depends on the enhanced PPS matrix ductility and toughness at T > Tg. An acoustic emission (AE) technique was used to investigate the correlation between the energy released during translaminar cracking and the cumulative AE energy/events for different stress concentration factors. Fibers breakage appears to be not very energetic from the AE standpoint. Finally, blunting is instrumental in increasing the strain energy release rate in specimens with low-stress concentration factors, due to large plastic deformations at the crack tip.

Incremental sheet forming is a flexible forming process based on the sheet progressive localized deformation where a forming tool follows a trajectory predetermined in advance by CAD/CAM programs. Although it is a slow process compared to conventional processes, this relatively new technique is very adequate for prototyping and small series production since it does not require complex tooling (die, punch, etc.). This paper presents a numerical and an experimental study of the Increment Sheet Forming process for a spiral toolpath. A 30 mm depth conical forming part is considered for this purpose. The experimental forming operation has been conducted on a 3-axis milling machine and the experimental data analysis was performed using a Kistler measurement system and a 3D scanner. Moreover, a Finite Element simulation has been realized in order to predict the evolution of the forming forces and the part final profile. The numerical results were in good agreement with the experimental ones. Moreover, the analysis of the scanning data has successfully restituted the part final profile and the surface details.

Recently, Disassembly Sequence Planning (DSP) plays an important role in the life cycle of mechanical products. Disassembly specification during the design phase of a product is considered as a great interest of engineers and designers. This paper presents an automated DSP based on Particle Swarm Optimization (PSO). First, the collision test is performed by the use of the interference test tool of the CAD software in order to identify all possible interferences during the components’ motion. Then interference matrices are generated to ensure the feasibility of disassembly operations. Next, a PSO algorithm, based on the regeneration of DSP, was performed to optimize the DSP using an objective function. Various criteria such as part volume, tools change, directions and maintainability of usury component are considered. Finally, to highlight the performance of the developed approach, an implemented tool is developed and an illustrative example is studied.

Pipe failure and leaks are frequent phenomena in urban areas. In order to minimize the risk of long-term leakage, nearly 60% of drinking water systems are renewed with third-generation polyethylene pipes, PE100. Due to its characteristics, it is a material of choice for water supply networks. However, the presence of a defect can lead the pipe failure under the effect of transient flow. In order to examine this problem, the cracking behavior of PE100 pipes with a defect has been studied. Using burst tests and finite element modeling, we have demonstrated that the concept of elastic-plastic fracture mechanics, the J-integral, can define with acceptable precision the crack initiation and the failure behavior of PE100 pipe. The J-integral value at the time of appearance of the damage zone, plastic strain-hardening, is considered numerically to be the value of the toughness. This allowed us to define the pressure leading to the crack initiation. The results are compared with the experimental burst pressures.

The plastic anisotropy of a sheet is measured by performing tension tests as well as by shear tests in different loading directions. In this paper, the main objective is to model the behavior of a 2024 aluminum alloy from experimental simple shear tests from several directions relative to the rolling direction. First, an experimental device of simple shear tests and the studied material are described. Second, the experimental results in terms of hardening curves are presented on three loading directions. In order to further refine the experimental part of this work, microstructural observations were conducted through transmission electronic microscopy (TEM) to show interactions between the precipitates and dislocations in studied material. Finally, several hardening laws are used to describe the isotropic hardening such as Hollomon law, Voce law, and Bron law. By smoothing experimental hardening curves shear stress–shear strain a selection is made in order to choose the most appropriate hardening law to identify the anisotropic parameters of the studied material.

In this work, we expose a closed-loop production system which has great similarity with the Kanban system as the Work-in-Process (WIP) is constant (CONWIP). This system is a multistage single product and it supports more than one machine at every stage. These machines can have different characteristics and they have limited capacity of buffering. We consider also that there is a preference for a machine usage in each stage. We use a Closed Queueing Network (CQN) with a repetitive blocking mechanism to model this system. The used resolution approach is the Maximum Entropy Method (MEM). In the first place, we look for the optimal WIP to keep in this system with respect to a production rate. In the second place, the routings to machines in the same stage are evaluated regarding the buffering capacity and the machine characteristic. We present some numerical results on a simple two-stage production system which holds the same number of batches looping. Interesting perspectives for the development of the presented model are looked over.

Crack paths prediction is one of the most challenging of fracture mechanics. The difficulty in this seek is how to obtain numerical models able of predicting unknown crack paths. One of these models is called the phase-field approach. It represents cracks by means of an additional continuous field variable. This model approximates a sharp crack with a diffuse crack phase-field where a characteristic length regularizes the crack topology and a crack energy density describes the energy dissipated in order to break a brittle piece. This method avoids some of the drawbacks of a sharp interface description of cracks. The phase-field model for brittle fracture assumes quasi-static loading conditions. However, dynamic effects have a great impact on the crack growth in many practical applications. Therefore, this investigation presents an extension of the quasi-static phase-field model for the fracture to the dynamic case. Experiment tests will be presented in this work in order to study the efficiency and the robustly of phase-field approach for modeling brittle fracture and capturing complex crack topologies.

Electrical discharge machining EDM is used in many industry sectors to machine conductor or semiconductor materials: hardened steels, ceramic alloys, some composites, and diamond. The aim of this paper is to develop a mathematical model of the surface quality of 36CrNiMo16 in EDM using the experimental design method: full factorial design 22. The statistical method of analysis of variance ANOVA, has allowed us to identify the significant effects of cutting parameters (discharge current I and the electrical resistivity of the electrode material ρ _e ; Electrolytic copper (Cu–A1) and Graphite (Gr)) on the surface quality. With Taguchi method, it was possible to determine a mathematical model of the surface quality described by the average roughness Ra. Indeed, an electrolytic copper electrode with a relatively low current (I = 8 A) generates a better workpiece surface quality. Therefore, the nature of the material’s electrode influences the surface quality of workpiece.

This paper deals with design problems of a complex technical system. Thus, a new design approach is proposed, which the consideration of static and dynamic requirements is done simultaneously and globally in the preliminary design phase. The proposed design approach is applied on the sizing case of an active MacPherson suspension system. Indeed, in this work, we succeed to integrate the dynamic behavior of the MacPherson suspension in the early design stage. In addition, its dynamic requirements are formalized in the form of algebraic constraints defined by a set of equations and inequalities. The generated solution is the set of acceptable values of design variables satisfying simultaneously static and dynamic requirements. This coupling between the static and dynamic sizing steps in the proposed design approach avoids over-sizing of the system. It also avoids resizing loops in case of failure, which saves significant computation time and reduces the cost of design.

During milling process, the vibration is an unavoidable phenomenon which causes damage in the tool and spindle bearings and leads to poor dimensional accuracy and surface finish of the workpiece. With the ultimate goal of vibration suppression of a thin-walled workpiece during milling process, this paper provides a comparative study of the dynamic behavior simulation of a cantilever rectangular thin plate submitted to a milling operation with and without passive dynamic mass-spring absorbers attached to it. The simulation is carried out taking into account the Kirchhoff model for the plate and the Moradi et al. (2015) model for the cutting force of milling. To solve the equation of motion of the plate with the finite element method the MATLAB software is used. The plate natural frequencies and mode shapes are first identified and then two cases of the plate deflection are determined by the cutting force and taking or neglecting additive absorbers. The obtained results show that the attachment of vibration absorbers to the plate workpiece enlarges its range of natural frequencies. Thus, it can minimize undesired vibration and improves the milling conditions and the surface quality. The proposed vibration absorber design includes other advantages such as design simplicity, intuitive clarity, and hardware and development effective cost. However, the plate deflection remains relatively high because this type of vibration absorber is efficient just in case of one resonance frequency.

Fracture mechanisms in solids are governed by complex fracture phenomena such as crack initiation and multiple crack branching. Phase-field models are used to simulate crack propagation in materials subjected to mechanical loading. This approximation reduces the implementation complexity for fracture mechanics problems as it removes the need for numerical tracking of displacement discontinuities. This is accomplished by introducing a new damage variable representing the diffuse crack topology which is controlled by a numerical regularization parameter. Already, due to nonconvexity of the regularized energy functional, a robust staggered solution scheme based on the decoupling algorithm is used. An optimized computing method is presented. We propose quasi-static crack propagation where the damage variable is activated only if the maximum stress in the specimen reaches a critical value σ_c. This methodology reduces the time computing by 20%. A parametric study is done on the specimen geometry to study the ability of the algorithm to provide the crack path. We are interested in the determination of the influence of geometry of specimen on the evolution of energies and the crack path.

Thermal energy storage got a significant role in the solar energy conservation in order to expand its use over time. To exploit solar energy continuously, we require a storage energy system. Phase Change Material (PCM) is used in this kind of systems in order to store a great amount of thermal energy. In fact, Latent heat storage in a PCM is very interesting because of its high-energy storage density and its isothermal behavior during the phase change process. Hence, heat accumulated during sunshine period can be restituted to be used for air conditioning purposes in buildings. This work concerns the solidification in the presence of the natural convection of a rectangular phase change material exposed to a cold air flow along the conducting side walls. With this intention, the first stage includes the presentation of a numerical model based on the conservation equations, treated by finite volume method (two-dimensional model) coupled to an enthalpy formulation (source terms). This numerical approach having like objective to follow the evolution of the various parameters characterizing the phenomenon of phase change (liquid–solid interface and a liquid fraction) during all the processes of solidification as well as the temperature and the velocity distribution in the PCM storage systems. Also, we give in this study the transient evolution of the longitudinal air temperature profiles.

The present study presents a numerical simulation of the hydrodynamic behavior inside a scraped surface heat exchanger (SSHE) which includes Archimedes’ screw instead of using scrapers. A 3D CFD code is used in order to characterize the flow pattern and the apparent viscosity distribution in the heat exchanger for Bingham fluids. With that purpose, the resolution of the conservation equations of continuity and momentum equations are conducted using the finite volume method. The effect of dimensionless numbers (rotational Reynolds and axial Reynolds) on the hydrodynamic behavior is studied. Numerical investigation shows that the lowest apparent viscosity values are localized close to the stator wall and near the rotor of the exchanger and the highest values are next to the Archimedes’ screw. Studies indicate also that the strongest shear rates values are in the space between the tip of the Archimedes’ screw and the stator wall.

In this paper, the problem of heat transfer by Al₂O₃–water nanofluid in the square cavity is studied numerically. The bottom and top walls of the cavity are kept at constant temperatures T_h and T_c, respectively, while the tow horizontal walls are supposed to be adiabatic and insulated. Again the effects of the thermal conductivity, the dynamic viscosity, the solid volume fraction, and the particle size on heat transfer nanofluid are discussed. We propose two models for viscosity and thermal conductivity of Al₂O₃–water nanofluid as functions of nanosolid concentration and diameter size more precise than those given by the theory and valid at room temperature. Numerical results show that the heat transfer is influenced by the particle size and the solid volume fraction.

A 3D numerical study of thermal regulation system of Rapid Heat Cycle Molding (RHCM) process producing smartphone cover has been undertaken. In order to succeed an RHCM operation, so as to improve the part quality and the process productivity, heating/cooling channels design is of great importance. For this purpose, we propose in this study the optimization of geometric parameters of heating/cooling channels. The concerned geometric parameters are heating/cooling channel diameter, distance between two successive channel and distance channel–cavity surface. The thermal behaviors in mold and polymer domains are predicted by the commercial Finite Volume Analysis software Fluent 6.3.26 in cyclic transient regime. It was shown that a regular state is reached rapidly, since the second molding cycle. Thermal responses have shown that increasing heating/cooling channels diameter promotes the RHCM process productivity, but, at the same time, generates an uneven temperature distribution and consumes a significant energy. With regards to heating/cooling channels spacing, it has been demonstrated the advantage of increasing the distance between two consecutive channels. However, increasing the distance channel–cavity surface contributes to balance the temperature distribution at the cavity surface, but it affects the RHCM process productivity by increasing the molding cycle time.

Reducing the noise generated in the industrial environment becomes the main objective of industrial designers in many applications (building, transport industry, etc.). The passive control represents one of the used methods to achieve this objective. It is based on the use of acoustic absorbent materials like porous materials, Helmholtz resonators, or perforated plates, etc. In order to obtain high-quality acoustic absorbers, the acoustic performance of each element is used and sometimes coupled to increase the total acoustic absorption of the liner. In this study, three industrial acoustic liners are studied: porous material, porous material with perforated plate, and perforated plate with air cavity. The liner characteristic impedance is defined using the material and the plate impedances. The porous material impedance is formulated by two models: the Delany–Bazley and the Lafarge–Allard ones. A comparative study is elaborated in order to show the impact of plate and material parameters variation on the acoustic absorption coefficient.

Rapid Heat Cycle Molding (RHCM) is a new thermoplastic molding technology. The principle of this process consists in a rapid heating of the mold until a suitable temperature. After the filling stage, the cooling phase begins and continues until reaching the ejection temperature. And so on for the following RHCM cycles. In this paper, a three-dimensional numerical study of thermal behavior of RHCM mold for complex shaped automotive part production has been undertaken. Numerical simulations of heat transfer in cavity/core plates domains, polymer and coolant domains, in a cyclic transient regime, have been carried out. To do this, Gambit 2.3.16 has been used to generate the meshing and the commercial software Fluent 6.3.26 has been used to solve the CFD problem. The spatio-temporal behavior within horizontal and vertical channels has been studied. A progressive increase in the coolant temperature during its passage through the mold has been proved. As regard to the temperature at the outlet of the channels, a progressive decrease during the cooling phase has been demonstrated. Moreover, in this research work, we have highlighted the significance of the study of thermal behavior in the cooling water domain (contrary to the hypothesis which assumes a constant temperature of the coolant taken in previous researches) to provide accuracy of the predicted RHCM cycle.

Engineering Change Management methods lead to assess impact of engineering changes and evaluate their propagation effects. In this paper, we propose a novel classification of Engineering Change Management methods according to their dependency model: (i) theoretical dependency model and (ii) a posteriori dependency model. A dependency model is needed to assess the change effect on one parameter after changing the value of another one. Three reference methods are presented here in details to explain the differences between these two types of dependency models and their usability according to designer decisions. The comparison shows that a theoretical model is generally a deterministic model that request a lot of knowledge and expertise in different areas. Besides an a posteriori model is based on probabilistic data and uses simple techniques and tools.

Energy harvesting from piezoelectric devices is a promising technology which is used to convert ambient energy extracted from the environment into electrical energy in the aim of supplying power for small electronic devices. Unimorph and bimorph cantilever beams have been used as basic piezoelectric energy harvesters. In this paper, a bimorph piezoelectric cantilever beam under base excitation is considered. An analytical model based on the Euler–Bernoulli beam assumption has been used to estimate the generated power. Series and parallel connections of the two piezoelectric layers are considered. To make an objective comparison of the generated power by several harvesters, the first natural frequency of the beam has been fixed by increasing simultaneously the beam thickness and the tip mass. The calculated frequency responses associated to the bimorph cantilever beam without tip mass have been validated based on the previous publications. It has been found that an increase of the tip mass and the beam thickness leads to a higher power generation. More power is produced in the case of a series connection.

With the ultimate goal of prediction species dispersion and pollution transport using computational fluid dynamics (CFD), this paper evaluates the performance of two different modeling approaches Reynolds-averaged Navier–Stokes (RANS) standard k-e, and Large Eddy Simulation (LES) applied to pollutant dispersion in an actual urban environment downtown Hannover. The modeling is based on the hypothesis neutral atmospheric conditions. LES is chosen to capture the effects of velocity randomness of the pollutants convection and diffusion. Computer-aided design, CAD, of Hannover city demonstrating different topologies and boundaries conditions, are cleaned, then in fine grids meshed. Pollutants are introduced into the computational domain through the chimney and/or pipe leakages. Weather conditions are accounted for using logarithmic velocity profiles at inlets. Simulations are conducted on 80 cores cluster for several days. CH₄ distributions as well as streamlines and velocity profiles conducted on reasonable results. The major interest of presenting work is that it involved a large group of real buildings with a high level of details that can represent the real case of the problem.

In the last few years, energy harvesting using piezoelectric materials has become a popular research topic because of its efficiency for converting vibration energy into electrical energy. In previous research studies, the shape and size of the harvester have been optimized for maximum power output density using analytical, numerical, and experimental approaches. This paper presents a finite element model of a bimorph piezoelectric energy harvester. The model is used to study the effect of load resistance on the resonant frequency and the generated power. The harvester consists of a clamped-free composite cantilever beam composed of an elastic substructure bracketed by two identical piezoelectric layers which are connected to a resistive load. An electromechanical finite element formulation for the dynamic analysis of the problem is first presented. The associated variational formulation is written in terms of structure displacement and electric potential in the piezoelectric layers. The finite element model of the bimorph energy harvester has been implemented on COMSOL Multiphysics software. It has been concluded that the energy harvester generates a maximum of electrical power output when the structure vibration matches the first natural frequency of the harvester and the optimal resistance load is connected to the piezoelectric layers.

Active vibration control (AVC) is used to overcome the limits of passive control. This chapter presents a design of an active vibration controller for a rotor bearing system using active piezoelectric patch actuators bonded on the surface of the rotor shaft. These devices are used to compensate the unbalance forces by applying control moments. The finite element method is used to construct a discrete rotor bearing system model. The design uses proximity probes to measure lateral vibration of the rotor bearing system. A Linear quadratic regulator (LQR) controller based on a full state feedback is designed to provide the adequate activation power to the piezoelectric patches. Rotordynamic analysis is carried out to obtain the Campbell diagram, the natural frequencies, and the critical speeds of the rotor bearing system. The designed active vibration controller reduced significantly rotor lateral vibration at constant rotating speed. A higher reduction rate has been obtained at the first critical speed.

In a planetary gearbox, there are multiple sources of vibrations due to the complexity of the gearbox since the latter contains multiple components (Sun, Carrier, Planets, and Ring) witch all of them are in mesh. In addition, the complexity of the planets motion (two rotational motions) affects the vibration collected in experiments, because the distance between planet and the transducer is time-varying. Hence, vibrations collected have not the same level: when the planet becomes closer from the senor, vibration level increases and vice versa. In this study, a linear two-dimensional lumped parameter dynamic model is developed in order to predict modulation phenomenon in a planetary gearbox. This model is based on novel description of the vibration of different components of the planetary gear taking into account the variable vibration transmission path. Numerical simulations show the ability of this model to describe this phenomenon with clear amplitude modulation in time signal.

This paper presents an experimental study to identify and characterize the different mechanisms of failure in the ±55° filament-wound glass/polyester composite. Acoustic emission (AE) was chosen as an experimental means of expertise. In this context, a relevant tensile test with in situ acoustic emission monitoring were conducted. The studied specimens were manufactured by filament winding. Indeed, first a tube is obtained by winding a mandrel with the desired draping and is then cut along the longitudinal axis to obtain wound test specimens having a small curvature. The discrimination of the different types of possible damage was obtained following the exploitation of the signals performed by the conventional mono-parametric analysis. This method assumes that each burst generated carries a specific signature to a generator mechanism. The amplitude distribution is the descriptor on which is based this study. The efficiency of the employed experimental strategy was confirmed after microscopic observations of specimens through the Scanning Electron Microscopy (SEM).

Marine and land environment is deeply affected by NPK company phosphogypsum storage in Sfax city. A part of Taparura project aims to confine this pile of partially or totally heavy metal pollution by creating a sealing wall released by a material made of bentonite and cement waterproof. This study focuses on a methodology for formulating a cement bentonite grout to construct the screen. First, a synthesis bibliography introduces the bentonite and cement properties material composition as well as the methods of formulation and standardized tests. Second, an experimental study was carried out to formulate the cement bentonite material. The physical properties of fresh and hardened material as well as its mechanical properties were determined. This experimental approach has permitted the determination of B/W _B , B/C and W _T /C ratios of the BC grout and the strength properties of the projected grout. Moreover, the properties of grout in fresh state of bentonite cement are in a good correlation with the desired conditions for the screen execution. The vertical permeability obtained is so low which limits greatly the flows through the screen. The Young modulus of cement bentonite material is near the soil modulus which conducts to the same strains in both soil and screen thereby reducing micro cracks in screen.

There is no doubt that the industrial revolution has a monumental effect on the prosperity and the improvement of human conditions but on the other hand the bill was too expensive due to environmental degradation especially. Indeed the weather changing and global warming are directly linked with energy consumption. Industrial manufacturing is one of the biggest consumers of energy which needs a deep care especially in machining sequences to reduce energy consumption and to achieve the balance of humanity. To reduce the waste of energy during machining sequences, a new numerical approach to predict machine tool energy consumption is proposed in this study. It is about the spindle rotation and axis feed modeling as well as considering a nonlinear behavior between the tool and the workpiece during the manufacturing process. The proposed model provides an accurate tool for process planning in metal cutting which helps manufacturers to determine the optimal energy process plan.