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This book covers a variety of topics in mechanics, with a special emphasis to fluid mechanics and energy transfer. Chapters are based on selected contributions presented during the Algerian Congress of Mechanics (CAM 2017), held on November 26 - 30, 2017, in Constantine, Algeria. The book covers theoretical analysis, modeling, and numerical treatment of performance-related problems of new refrigeration systems, heating and cooling. It reports on experimental research to solve problems related to the flow of microfluids, and relevant applications in the areas of chemical engineering, biochemistry, biomedicine and renewable energy. Further topics include methods for maintenance of mechanical structures, strength, wear, fracture, damage and life of structures, and image processing solutions for the design and 3D manufacturing of mechanical parts. Improvement, control and regulation of urban road traffic are also discussed in this book, thus offering a comprehensive, practice-oriented reference guide for academics and professionals.

### Mixing-Time in T-Mixer Reactor

The mixing of fluids at micro-scale is one of the most important operations in the development of micro-fluid systems for applications in chemical and biochemical engineering, biomedical systems. Attaining rapid mixing is a challenging task because mixing mainly relies on molecular diffusion across the interface of the fluid stream in micro channels. The geometry of the T-mixer with non-coaxial inputs in which the reagents are mixed can have a great influence on the distribution of nanoparticle products (on the preparation of homogeneous and monodisperse nanoparticles). The T-mixer is designed in such a way that the entering jet forms a vortex and generates a turbulent swirling flow: the fluid velocity profile presents an instant formation of a vortex in the fluid contact area. The vortex package consists of elementary vortices of both reagents, the size of which depends on the amount of energy injected into the system. This article focuses on the experimental validation of our numerical model of the T-mixer, by measuring the height (Zi) for obtaining this micro-mixing. For the numerical model, we used the Computational Fluid Dynamics (CFD) to simulate fluid flow in the T-mixer with the k-ε turbulence model using Ansys Fluent software. Numerical and experimental values of Zi mixing converge.
Khaled Oualha, Mounir Ben Amar, Andrei Kanaev

### Thermal Hydraulic Modeling of a Nuclear Reactor Core Channel Using CFD; Application for an EPR

An EPR (Evolutionary Pressurized Reactor) is a third generation nuclear reactor. It works at high temperature and high pressure and uses water as coolant and moderator. The coolant flow is axial between four cylindrical fuel rods, this configuration is the nuclear reactor core channel presented and studied here. The thermal-hydraulic nuclear reactor core channel analysis is done thanks to the conservation equations of mass, momentum and energy. Turbulence is modeled by the two equation model. The heat generation law, in the fuel, is introduced thanks to a User Defined Function (UDF) available in the used CFD code. Mesh of the numerical domain is done with Gambit and the set of equations is solved by finite volume method implemented in the code FLUENT. The mesh sensitivity is checked before resolving the problem. The application for an EPR’s thermal-hydraulic channel is presented. A parametric study is done. The evolutions of pressure, fluid temperature and clad temperature, for a sinusoidal behavior of the nuclear reactor power, are presented and commented. A comparison of the design temperature of the cooling fluid at the exit of the nuclear reactor core and the one calculated by CFD shows that the relative difference don’t exceed 3.3%.
Kamel Sidi-Ali, Djaber Ailem, El Moundir Medouri, Toufik Belmrabet

### Thermochemical Modeling in Hypersonic Reactive Flow Behind Strong Shock Wave

In this study, a one-dimensional post-normal shock solver in hypersonic ionized air flow was developed to study the effect of the physical-chemical phenomena that occur at high temperature. To simulate this case, the upstream air flow is considered with 2 species (21% of O2 and 79% of N2). Behind the shock wave, the Park’s chemical kinetics model with 11 species (O2, N2, NO, O2+, N2+, NO+, O, N, O+, N+, e) and 49 chemical reactions is used. The vibration-dissociation coupling is taken into account according to the Park’s model for which the activation temperature of the dissociation reactions is $$T_{a} = T^{q} T_{v}^{1 - q}$$. The energy exchange model between translation modes and vibration modes is described by the Landau-Teller formula where the species relaxation time is based on the Millikan-White formula, including Park’s high-temperature correction. The numerical model of the flows governed by the Euler equations supplemented by the equations of the chemical kinetics and the system of equations obtained is discretized by the finite difference method, good agreement between the relaxation zone obtained and those obtained by Panesi for the two trajectory points corresponding to t = 1634 s and t = 1643 s of the Fire II re-entry vehicle.
Youcef Ghezali, Rabah Haoui, Amer Chpoun

### Kinematic and Dynamic Modeling and Simulation Analysis of a Cable-Driven Continuum Robot

Continuum robots are the behavioral-extension of hyper-redundant robots which can belong to biologically inspired robots. These robots differ fundamentally from the rigid robots by having an unconventional structure. They are conceived to mimic the extraordinary capacities of some remarkable structures such as elephant trunks, tentacles and snakes. These robots offer many advantages in terms of high dexterity and maneuverability, handling and grasping objects as well as its lightweight mechanical structure. In this work, we present a kinematic and dynamic modeling of a class of continuum robots namely cable-driven continuum robot and precisely for a planar case. At first, a design of the planar cable-driven continuum robot (P-CDCR) is constructed by using Solidworks software. Then, the mathematical expressions of kinematic models are derived under the assumption of constant curvature of inextensible bending section with zero torsion. The dynamic model of the considered P-CDCR is derived by using the Euler-Lagrange method. Some numerical examples, through Matlab/Simulink software, that validating kinematic and dynamic models are presented and discussed. In addition, to validate the effectiveness and the accuracy of the proposed dynamic model, the obtained results from analytical model are compared to that made up in the Solidworks software through static and nonlinear dynamic cases. From the analysis, it is found that the obtained results for both software are similar to the validating proposed model.
Ammar Amouri, Chawki Mahfoudi, Selman Djeffal

### A Novel Constitutive Modelling for Spring Back Prediction in Sheet Metal Forming Processes

The purpose of this work is to present, by the mean of a numerical study, an elastoplastic constitutive model of metals which is introduced in finite element code for predicting spring back phenomenon in sheet metal processes. A simple case study is proposed “L-bending process” which is widely used for mass production. An accurate prediction of spring back is very delicate due to non-uniform stress distribution in the sheet thickness. Knowing that, the material behaviour modelling and its incorporation into the finite element code is considered as an important step in the numerical analysis of spring back, a statistical and physically based modelling for predicting the elastic return in the sheet after a bending operation is proposed. Taking into account the material heterogeneities; on the basis that the metallic alloys are discrete and heterogeneous, the proposed model called compartmentalized model (or hybrid model) is based on the combination of mechanical behaviour law at a local level and statistical distribution of mechanical properties. By way of comparison, the advantages of the proposed model compared to classic phenomenological models were discussed. Tests have been carried out on commercially pure titanium sheets (T40 alloy), that is increasingly used in aircraft sector because of its specific properties.
Ahmed Maati, Laurent Tabourot, Pascale Balland, El Hadj Ouakdi, Salim Belaid

### Microstructural Analysis of Nickel-Based Composite Coatings and Their Effect on Micro-hardness and Nano-indentation Behavior

The coating reliability and failure are inextricably linked to its microstructure, from which all the other characteristics are derived. Based on the properties obtained from multiscale assessments, after a thermal flame spraying processing applied on X18 carbon steel, this investigation aims at expounding the contribution of the prior grit blasting treatment and the presence of the Ni-based bonding layer in determining the coating characteristics. For that, a NiCrBSi self-fluxing alloy reinforced with tungsten carbides was selected to realize the deposits in the open atmosphere, using the acetylene as fuel. The characterization of the coating was carried out through optical microscopy, micro-hardness measurements and nano-indentation tests. Quantitative data were estimated by processing the obtained optical micrographs. The results show that the coating contains fine precipitates and has dendritic microstructure surrounded by a eutectic phase. The micro-hardness profile proved that the prior grit blasting treatment had induced a substrate hardening near the interface where the hardness roughly achieves 500HV. The cooling in the air environment has activated the initiation of cracks. The nano-indentation results reveal that the elastoplastic response of the matrix differs depending on the nature and the proportion of phases.
Rabah Azzoug, Fatah Hellal, Yamina Mebdoua

### Effect of Slag and Natural Pozzolan on the Mechanical Behavior of Recycled Glass Mortars

The incorporation of mineral additions in cementitious materials produces a granular effect, a physico-chemical, a micro-structural effect and a chemical effect. To study the effect of mineral additions on the mechanical properties of recycled glass mortars, we propose to use a specific methodology based on the progressive substitution of cement volume (10, 20, 30%) by mineral admixtures whose absolute volume of solid phases and workability are kept constant. The aggregate used to make mortar mixtures is recycled sand resulting from the grinding of glazings known by their reactivity with respect to the alkali-silica reaction. The mineral admixtures used are different by their mineralogical nature, chemical composition and granularity, for this study we considered two mineral admixtures (granulated blast furnace slag and Beni-Saf’s natural pozzolan). After 28 days curing time, the Zwick/Roe II Z020 universal machine was used for bending and compressive strength tests. At the end of each test and data collection the stress-strain curves were obtained, from which strengths, strains and energy were determined and the elasticity modules deduced, which were compared with reference values without mineral admixtures. The different results show that the incorporation of granulated blast furnace slag and Beni-Saf’s natural pozzolan into fragile recycled glass mortars improves their mechanical behavior and ductility.
Zineb Douaissia, Mouloud Merzoud

### Buckling Analysis of Isotropic and Composite Laminated Plates: New Finite Element Formulation

In this paper, a simple 2D quadrilateral finite element has been developed based on Reddy’s third order shear deformation theory for the buckling behavior analysis of isotropic and composites laminated plates. The developed element is a C0 four-nodded isoparametric with seven degrees of freedom (7DOF) at each node. Each node has only three translation components, two rotations and two higher order rotational degrees. The nodal approximation is expressed from the Lagrange interpolation for the considered degrees of freedom in each node and for the element geometry through all coordinates. In particular, the selective numerical integration is introduced for the present FE formulation in order to achieve good results and to alleviate the shear locking problem. The model is able to provide a parabolic distribution transverse shear stress through the thickness and satisfying zero boundary conditions at the top and bottom surfaces of the plate without any remedy to correction factors. The performance and reliability of the proposed formulation are proved by comparing with those obtained analytically by three-dimensional theories and those obtained by the same order models in the literature. The results indicate that the proposed formulation is promising in terms of the accuracy and the convergence speed for both thin and thick plates.
Khmissi Belkaid

### Prediction of Optimal Lifetime of the Tool’s Wear in Turning Operation of AISI D3 Steel Based on the a New Spectral Indicator SCG

In order to follow the wear of the cutting tools, the monitoring of the machining processes plays a very important role in the minimization of the durations of breakdowns and the prevention of the appearance of certain undesired phenomena such as chattering, excessive wear or breakage of the cutting tool. In this context, the strategy adopted in this study is to use a methodology that combines numerical and experimental to track the wear and damage of cutting tools. The method is based on the analysis of the vibratory signatures measured in order to predict the lifetime of the tool during machining before its final degradation. As a first step, the work consists in the acquisition of data resulting from the cutting process as a function of the parameters of the cutting regime. Secondly, the work is dedicated to the processing of the measured signals using a new spectral indicator called the spectral center of gravity. The SCG spectral indicator has shown its power of predicting the transition from the phase of normal wear to that corresponding to the catastrophic wear of the cutting tool. The results obtained allowed to study the phenomena of vibration and then to predict their optimal lifetime.
Mohamed Khemissi Babouri, Nouredine Ouelaa, Mohamed Cherif Djamaa, Abderrazek Djebala, Septi Boucherit, Nacer Hamzaoui

### The Evaluation of the Dynamic Response of the Moving Exciter Due to the Irregularities of the Slab

The passage of a moving exciter at different speeds automatically generates effects that are enhanced by their natural values. The mobile exciter dynamic response and especially the vertical displacement were investigated in this work. The dynamic behaviour of a mobile exciter witch modeled with seven degrees of freedom model was studied. The path surface is modeled by a continuous orthotropic thin plate in order to approximate the real behaviour of the moving exciter. The path surface irregularities are considered as the contact surface with different states. The modal and Newmark integration methods have been used to solve the coupled path surface–mobile exciter equations of motion. One presents the results which show clearly the influence of the path surface irregularities on the dynamic response of the mobile exciter. Using the local estimate method drastically reduces the number of differential equations of the free motion of the path surface to be solved and enables it to be incorporated into structural analysis software, as there is no required integration. This is a major advantage over approaches that rely upon a Rayleigh-Ritz method and is demonstrated an interactive software CDPR which we are developed. CDPR enables a radical reduction in computing time when compared to the published works.
Moussa Guebailia, Nouredine Ouelaa

### Rolling Bearing Local Fault Detection During a Run-Up Test Using Wavelet-Filtered CEEMDAN Envelopes

In the context of the fast technological evolution and high reliance on machines, surveillance became critical and important. One of the most essential parts that need continuous inspection is bearings. For that purpose, many techniques have been developed on the base of lubricant analysis, infrared imaging and vibration analysis to make sure that maintenance operations are executed in the right time and guarantee a continuous production. Vibration analysis is often used for diagnosing constant speed machines faults, but rarely tested under non stationary conditions. In this work, the practicability of a hybrid vibration-based method, constructed on the base of the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) and the Wavelet Multi-Resolution Analysis (WMRA), is tested for rolling bearing local fault detection under variable conditions, where the machine experiences a run-up test. The captured signals have been decomposed with CEEMDAN to extract the bearings vibration response, the extracted signals have been then filtered with WMRA trying to isolate the impulse train generated by bearing faults. Two criteria have been proposed in order to recognize the best modes and details: The bearing resonance frequency coverage and Kurtosis values. The results demonstrate that the presented hybrid approach has effectively highlighted the bearing faults in the non-stationary conditions, with both simulated and experimental signals.
Mohamed Lamine Bouhalais, Abderrazek Djebala, Nouredine Ouelaa

### Industrial Reproduction of Objects with Freeform Surfaces Using Reverse Engineering Process

Parts with freeform surfaces used in the design and the manufacture of molds, etc. are machined on multiaxis CNC machines from their models which can be obtained using Forward Engineering or Reverse Engineering. If surfaces shapes are of medium complexity, Forward Engineering is appropriate. Reverse Engineering is adopted when surfaces shapes are of high complexity or their CAD models are unavailable. This process reduces the product development cycle and costs. It consists in reconstructing object CAD model from its 3D clouds of points. In this paper, an experimental approach is adopted for the industrial duplication of objects with free-form surfaces from 3D point clouds acquired using a Coordinate Measuring Machine—CMM—equipped with Laser Scanner. The conducted analysis highlighted that the reconstruction of the CAD model with a good accuracy depends on the clouds of point’s density and particularly in zones of high curvature variations. Consequently, the analysis of object surfaces to duplicate is a critical operation before scanning. In the same time, clouds of points must have optimal densities to facilitate their treatment and to minimize processing times. To validate the generated CAD, variances spectral analysis between it and original cloud of points must be done.
Sahla Ferhat, Mohamed Bey, Hassène Bendifallah

### Effect of Boundary Conditions and Damping on Critical Speeds of a Flexible Mono Rotor

This paper focuses on the identification and the dynamic analysis of a flexible multi-disc-mono rotor which is considered in the case where it is an asymmetrical and damped mono rotor. In fact, the rotors play important roles in rotating machines and particularly those mounted on hydrodynamics bearings and possess all sorts of particular vibratory phenomena which may product their divergence and even their failure under critical speeds. These later are function of dynamic rigidities of rotating systems. The presence of gyroscopic forces creates dependence between the rotating speed and the pulsation of structures. Then the dynamic analysis of the rotors is then necessary for their concept and design. The model chosen here is similar to that of Lalanne and Ferraris who just considered the supported-supported case only; and our case treats different values of the damping and boundary conditions. For this, we have taken the cases where the rotor is simply-simply supported, free-simply supported and free-free and we wanted to see their effect on the vibratory behavior by determining critical speeds and responses to synchronous and asynchronous forces. It was found that the damping affects the amplitudes of the responses to the synchronous and asynchronous excitations as well as the boundary conditions.
Saliha Belahrache, Brahim Necib

### Remaining Life Estimation of the High Strength Low Alloy Steel Pipelines by Using Response Surface Methodology

This paper presents a probabilistic study to estimate the remaining lifespan of cracked steel pipeline by using the response surface technique. The purpose is to assess the reliability index of the high strength low alloy steel (HSLA) pipelines for a limit state function without closed-form. The implicit objective function is approximated by a polynomial representing a quadratic response surface and the assessment of the failure probability is obtained using Second order reliability method (SORM). The presence of a semi-elliptical crack defect in the longitudinal direction of the pipe steel will intensify the stress field at the crack tip and will decrease the limit state function. Exhaustive and costly tensile and Charpy V notch tests prepared from the longitudinal direction of the parent tube were achieved in order to study the mechanical behavior of API X70 steel grade and integrating the uncertainties of the engineering model parameters through their probabilistic densities. The assessment of the stress intensity factor is conducted by using the finite element methods. The estimation of the reliability index and the probability of failure are carried out by coupling the mechanical model, and the finite element method based on the commercial code ABAQUS. This coupling based on the response surface methodology, could be used as a decision making support for any repair or replacement of the damaged pipeline.
Djamel Zelmati, Oualid Ghelloudj, Mohamed Hassani, Abdelaziz Amirat

### Implementation and Experimentation of (VSI) Applied for a Photovoltaic System

In this paper, the simulation and real time implementation of a space vector pulse-width modulation (SVPWM) control scheme to demonstrate the high performance of the photovoltaic inverter when dSPACE is used as controller. The design and the simulation of electrical operation of a photovoltaic (PV) system controlled by an intelligent method enabling to track the maximum power produced by the photovoltaic generator are described. The simulation was performed in the Simulink/MATLAB environment and the PV output voltage is represented by a DC power supply of the inverter. Furthermore, tests are performed on experimental platform to implement the developed algorithms of SVPWM inverter used to convert the produced dc voltage to a variable AC voltage. The experimental waveforms such as ac output voltages, current and total harmonic distortion are presented and analyzed.
K. Baali, S. Saad, Y. Menasriya, F. Zaamouche

### CFD Study About an Archimed Wind Mill

This study consists of a numerical simulation of the air flow on a new domestic wind turbine of the Archimedean type invented by a Dutch engineer in 2006; it takes the form of a repeated nautilus shell. this wind turbine is a little different from that of Marinus Mieremet in its design where the helicoidally curve is traced according to a data file, in our case the helicoidally curve is conical with angle of 30°, begins with a 5 cm of diameter (diameter of the rotation shaft) with a pitch of 1.25 m, this helix undergoes a circular repetition of 3 times. This wind Mill has given good results regarding the efficiency and the power compared to its lightness and installation cost for an average wind velocity of 8 m/s. The CFD study allowed obtaining the total pressure field, velocity field, velocity vectors, and streamlines around this Archimed Wind Mill (AWM). The behavior this flow is predicted. The force, torque and speed of rotation are extracted. And at the last the power of AWM is calculated by the theory of Betz limit or by the formula of torque. And therefore it is recommended for domestic use.
Nassereddine Hamdi

### Periodic Inspection Policy for a System with Two Levels of Degradation

The use of a mechanical system causes a permanent degradation of the latter. This degradation progresses from one level to another until the critical phase where the system is breaks down. To avoid these failures we must know the exact state of the system at every moment. Furthermore, the degradation states are only detected by inspections. Thus, in order to meet the economic and customer requirements at the same time, we must set an inspection policy that will allow us to optimize a certain criterion such as: minimizing maintenance costs, maximizing the availability duration of the system. In the present work, we are interested firstly in the modeling of a mechanical system, with two degradation levels, by a gamma process. The first level repre-sents the preventive replacement threshold where any exceeding of this threshold requires preventive maintenance on the system. While the second level is the criti-cal degradation, threshold that causes system failure. Secondly, the economic model of the inspection/replacement policy, in the sense of minimizing the total cost of maintaining the system in a replacement cycle, was developed. Finally, a numerical and graphical analysis of the sensitivity of the different mathematical models, with respect to their parameters, is carried out. We are interested by the modeling of a system, with two levels of degradation, by a gamma process. The sensitivity analysis of the mathematical model, whose solution is the optimal inspection/replacement policy minimizing the maintenance costs, is provided. The various models and quantities introduced are illustrated and analyzed in case of variation of their parameters by numerical examples.