Recent Developments in Mechanics and Design

A systematic study of overload-induced effect on fatigue crack propagation is presented. Effect of interspersed overload under constant amplitude load is simulated via modified virtual crack annealing (MVCA) model, which is based on crack closure phenomena. Study is performed on 304LSS (stainless steel) for various overload ratio and crack length. MVCA model prediction is validated using experimental data. Error analysis for studied cases has been presented.

Magnetic field assisted abrasive flow machining (MFA-AFM) is a realistic precision finishing process used for part finishing. The process has applicability in a wide scope of industries such as aerospace, automobile, prosthetic, and tool and die manufacturing. This article primarily emphasizes on the machining mechanism of MFA-AFM intending to understand the relationships among the machining parameters, the material removal rate (MRR), and the surface quality of soft, ductile aluminum tubes. Hydraulic pressure, magnetic flux, abrasive mesh size, no. of cycles, and media are the major machining parameters that influence the machining characteristics. The experiments have been organized and conducted by employing the design of the experiment technique. The analysis of variance (ANOVA) was presented to find the contribution of all model terms influencing the MRR, and percentage change in the surface roughness (%ΔRa). The experimental results disclose that the key contributor parameters to enhance MRR and %ΔRa are hydraulic pressure and magnetic flux followed by the no. of cycles. Higher-order response models for the prediction of MRR and %ΔRa have also been presented. The optimum machining conditions have been found from numerical optimization. Surface analysis was employed to characterize the surface integrity.

After the first introduction of 4D Printing in 2013, this new area has attracted researchers from academics and industries to explore novel possibilities. The foundation of the 4D Printing technology is primarily laid upon the similar process of 3D printing technology with additional requirements of stimuli environment and stimulus-responsive materials. In this article, three fundamental foundation pillars of 4D Printing, i.e., Smart Materials, Smart Designing, and 3D Printing Technologies, are reviewed. The literature concluded that the new dimension of time and exhibiting smart behavior differentiate 4D printing technology from 3D Printing. It was observed that 4D Printing is time-dependent, stimuli-dependent, design-dependent, and material-dependent. In this article, a review of the 4D Printing process is presented and summarized the two key features, i.e., Smart materials and Smart Design which draw the line between 3 and 4D Printing and pointed out the utility areas.

High-altitude balloons and sounding rockets are two near-space technologies. Together they can launch satellites to suborbital space. Rockoon's concepts were abandoned due to their inaccuracy. With an increase in nanosatellite development, there is an increase in affordable launches desire. This paper aims to discuss altitude stabilization and trajectory control techniques for an enhanced flight of high-altitude balloons. This paper's Stabilization techniques include Stratosail Balloon Guidance system, Dual Balloon System, Electrohydrodynamic Propulsion, and Cold Gas Propulsion system. Stratosail provides stability using the wing and rudder suspended at 10–15 km below the primary balloon. A dual balloon system provides stability by pumping in or venting out the atmospheric air to change the altitudes. It helps restrict trajectory within 25 km. Electrohydrodynamic thrusters ionize the surrounding air to produce thrust and propel the system in the desired path. The cold gas propulsion system provides a yaw moment for trajectory control. Using these techniques, a better flight of high-altitude balloons is expected, the stability helps in the proper launch of the rocket from the high-altitude platform. This paper provides a detailed literature review of these concepts. There is much future scope in the research field of stabilization and Trajectory Control of High-altitude balloons for Rockoons.

An interest in and advanced research in organic solar cells has grown due to their low-cost and flexible use in power devices, their environmental benefits, and their outstanding promise to be an economical and efficient technology for utilizing solar energy as a sustainable power resource. Much attention has recently been drawn to the use of organic solar cells with a bulk heterojunction active layer of a non-fullerene acceptor material, which has technical advantages for overcoming photon harvesting, charge recombination, and lower manufacturing costs. Efficiency, cost, and stability are the primary factors in these organic-based solar cells. However, to stay competitive with traditional solar cells, organic solar cell technology must be innovative and lead to a breakthrough to fill the gap in renewable energy. This article presents findings focusing on the significance of optimizing the organic solar cell concerning its organic semiconductor morphology and optical properties, power conversion efficiency, device stability, fabrication processability, and the organic solar cell’s enhanced performance with parallel tandem configuration about enhanced device development engineering.

The study of polymer composite structures under uniform external pressure is vital in the design of pressure vessels of submarines or submersibles in which hydrostatic pressure-induced buckling tends to dominate structural performance. Advanced grid stiffened structures show superior buckling resistance to that of the unstiffened. The present work mainly aimed at examining the effects of grid thickness, grid height, inner shell thickness, outer shell thickness, and the number of segments on the structural performance of ortho-grid stiffened vinyl ester/glass composite shells. Design of Experiments (DOE) was used to identify significant parameters and their effects on critical buckling pressure and the total volume of the structure. Parametric study of ortho-grid stiffened polymer composite structures was performed using ANSYS buckling analysis, for their survival at 1000 m depth of the sea. Approximations of critical buckling pressure and total volume of the structure in the design space were developed using Response Surface Methodology. These approximations with design constraints were used to develop the optimization problem which was then solved using Penalty Function Approach. The DESIGNEXPERT tool was used to perform an Analysis of Variance, develop approximations using response surface methodology, and finally find optimal design points. The results of the ANOVA of the parametric study indicated that inner and outer shell thicknesses of the stiffened composite shells had a significant effect on both critical buckling pressure and the total volume of the shells. The optimization results were compared with that of unstiffened shells of identical dimensions to estimate the weight saving due to the stiffeners. Volume saving of 30% compared with unstiffened structures achieved.

With the increasing levels of technology, the automobile sector is coming up with several changes to their existing designs of auxiliary parts. The main auxiliary part of any vehicle is a jack, which comes in various types, shapes, and sizes, where the effort required to use them varies. Some of these types include scissor jacks, floor jacks, bottle jacks, pneumatic/hydraulic jacks, high lift jacks, and stand trolley jacks. Among this for lifting the vehicles, mechanical or hydraulic jacks are used. In this paper, an attempt is made to minimize the effort applied using the jack to lift the vehicle in a very short time. We bring in the concept of the Trestle Jack, which uses driving motion from the vehicle to lift and lower trailer axles. For the model, the finite element analysis was carried out and the fatigue life estimation and optimization for material and size were executed as a case study. The trestle jack was optimized in terms of weight so that it eliminates the requirement of skilled labor and saves time for the operation.

In this paper, a technique is demonstrated to notice the end-effector’s Denavit Hartenberg (DH) parameters as per the necessity of the labor envelope. For this purpose, here we have used Roboanalyzer software. The manipulator’s gripper is designed in such a way to move and perform a particular task in a specific way. In recent research papers, simulation for the ARISTO robot functioning for welding a curved surface has been discussed. We aim to design and simulate the MTAB ARISTO robot integrated with a vision module that perfectly suits pick and place operation on the conveyor, upon which kinematics and simulation are done for the respective joints and links for the end effector. Motion analysis of the manipulator is shown on graphs as a time sequence of links and joints. Each of which is performed and done using RoboAnalyzer software.

The pressure blast wave generated by a shock tube was simulated using a computational fluid dynamics technique to investigate blast load due to pressure distribution on the wall which is located at the downstream of shock tube at a specified distance. In the present world, blast wave mitigation is very important to be produced as a defence system for military vehicles and commercial structures. An object is placed between the exit of the shock and wall for the calculation of blast load on a wall. Blast wave interacting with a circular object is placed at four different locations for the pressure ratio of 40 and 50, respectively, across the diaphragm. Numerical simulations are performed for blast wave which is produced inside a driver section by solving the unsteady, axi-symmetric Navier–Stokes equations using Advection Upstream Splitting Method with Third-Order Monotone Upstream Centred method for Conservation Law approach. It has been observed that the blast load on a wall decreases if the object is placed nearer to the shock tube exit and the blast load on a wall increases if the object is displaced towards the wall from the shock tube exit. The computed result demonstrates that when the pressure ratio in a shock tube rises, the maximum pressure on the wall also increases.

This paper deals with experimental investigations on the influence of notch-width ratio on the mechanical and electromagnetic radiation (EMR) parameters during tensile deformation in commercial aluminum and cold-rolled high yield strength copper. Mechanical parameters such as maximum stress at crack instability, plastic zone radius, stress intensity factor and elastic strain energy release rate, and EMR parameters such as maximum EMR amplitude, average EMR energy release rate and maximum dominant EMR frequency were chosen for analysis. Correlations between the mechanical and EMR parameters were established. The EMR energy release rate displays an excellent relationship with the elastic strain energy release rate, which may be a tool for determining the fracture toughness of the metals. The EMR parameters also exhibited an excellent correlation with the plastic zone radius. The EMR energy release rate has also displayed a smooth fit with the ratio of the product of lattice period and stress at crack tip instability to the stacking fault energy. The implications of our results for evaluating fracture toughness, crack growth monitoring, and dislocation dynamics during plastic deformation are discussed.

Magnesium represents a very attractive material for biodegradable orthopedic implants because of its capability to resolve the problem of stress shielding, osteocompatibility in addition to its biodegradability. Yet, pure Mg does not have adequate strength when exposed to body fluids as it starts degrading at a higher rate. The aim of this research is to study the effect of wire electric discharge machining on Mg-based alloy ZM21 to increase its effectiveness by surface grain refinement as a tool to limit the initial corrosion rate in body fluids (modulus of elasticity remains unchanged). Comparison of microstructural, mechanical, and in-vitro corrosion changes along with biocompatibility of the polished and wire EDM machined samples of ZM21 Magnesium alloy were performed in this study. The alloy experiences a change in grain size inthe recast layer formed on the machined surface which retards the initial degradation rate due to the occurrence of less number of high energy grain boundaries. Also ensures the production of corrosion resistive Mn2O₃ and Mn3O₄ compounds on the newly formed surface with MgO2 as the base.

Gas tungsten arc welding is a type of arc welding in which a non-consumable electrode of tungsten is used to weld. The electrode and weld area are protected by an inert shielding gas to avoid atmospheric contamination. This welding process is considered as a high heat input process which occasionally leads to the generation of non-uniform thermal stresses in the material that causes weld abnormalities like angular distortion. Where distortion is crosswise to the welding track and caused by shrinkage adjacent to the fusion zone ensuing change in the angle of the parts. Thus, it is important to predict the extent of these distortions to a certain level of accuracy so that remedial steps can be taken while selecting the input parameters to curtail the final angular distortion. In this research work, angular distortion is investigated during the GTA welding of two dissimilar grades of stainless steel i.e. 304 and 316. The effect of input constraints like current, welding torch angle and speed on the angular distortion of the plate was investigated by developing the mathematical model between the input parameters and its response by using the factorial approach. The results were analyzed using graphical representations.

Water plays a unique and crucial function on the globe but due to population growth, industrialization, the effects of climate change, the populace lacks access to adequate drinking water. Water 4.0, often known as “Digital Water,” is poised to change the water sector and address this threat to human survival. Given the highly localised nature of the contamination, it is also advisable to create local prediction models and assess at least multiple robust and applicable algorithms. Heavy Metals before settling on a final model and hybrid ML–DL models are very effective. For simple and sensitive application in the construction of Arsenic specific chromogenic and fluorescent probes, such as hydrogen bonding interactions, a definite sensing method and aggregation-induced emission (AIE); chemodosimetric approach; metal coordination. The detection of Arsenic and Fluoride ions was made possible by the development of two sensitive and ratio-metric fluorescent probes (probe I and probe II). Both Probes have a certain detection limit with a stable detection range. The developed smart sensor works on the fluorogenic principle and its design is divided into four modules such as sensing, measurement, control and display unit. Artificial intelligence prediction models can be utilised as a decision-making tool and to develop proactive environmental policy. International Centre for Clean Water (ICCW) is speeding the dawn of Water 4.0, which will lead to clean and sustainable water for all, through its implementation strategies in water treatment plants, industry and the community.

Geo-specific data of water contaminants are important and rare for water resources management. Smart sensors are a basic and powerful tool for managing water resources. Many technologies like Digital Twining, Automation, Smart Industries, and smart cities are designed with the help of real-time intelligent sensors. Lab-based sensing technology misses the location accuracy and the time. The location-based portable smart sensor is a key changer for the scenario. A smart sensor module is divided into 5 nodes such as Sensing Node, Controlling Node, Wireless Network Node, Alarming Node, and Power Node. For designing any module, it is very important to compare and select different parts and the components. This study consists of a detailed description of different nodes, controlling parameters, and selective parameters. Comparative parameters for the selection and designing of components are discussed in this paper. The primary objective of the study is to highlight the essential parameters and selection criteria, which are required for sensor designing inset of water resources management and to know about smart technology and different components, and select parameters for a specific application. Suitable nodes and components are selected and simulated for an optimized interface. The study shows the noble design of the sensor which is required for the detection of water contaminant (Arsenic) at the point of care.

In order to remain competitive in the market, industries have to manufacture more quality products and at the same time have to reduce costs. The main aim of any industry is to increase productivity to meet customer requirements. One of the techniques that industries use is the Line Balancing technique to enhance productivity and to reduce waste. Line balancing can be implemented to reduce the overburdening faced by the operator to distribute the work content equally among operators and at the point where bottle neck occurs. In this paper line, the balancing technique is applied in the crankshaft cell 3 assembly line in an automotive industry. The current study in the crankshaft cell 3 assembly line is carried out to remove wastes and to come up with ideas to solve them. After implementing the Line balancing technique, it resulted in a reduction of manpower from 4 to 3.

Vibration is an unwanted mechanical phenomenon which causes performance deterioration of dedicated equipment and critical electronic hardware. In order to reduce this vibration during the transportation of the dedicated payloads i.e. optical payload or microwave payload and critical electronic hardware such as atomic clocks, detectors etc., containers with vibration isolation systems are used. Traditional vibration or shock absorbing systems are big in size which makes the whole container huge and bulky. In our present paper, we try to characterize different types of springs (helical and wave) and develop a FEM methodology to calculate the stress and displacement of the springs under load. Generally, helical springs are used with shock absorber systems having large displacement areas. In this study, we have selected helical and wave springs [1] for our experiments and compared them for the fulfilment of our objective. The future aim of this study is to select a suitable spring which can be used with a small size damper in order to make a compact vibration isolation system which will provide the same load carrying capacity in a constrained space as that of a traditional system [2]. The CAD files of both the springs are modelled using Autodesk Inventor Professional 2019 and Creo Parametric 5.0, while the FEM methodology is performed using HyperWorks 2019 for both the springs. The theoretical calculations of the models are compared with the FEA results and then validated experimentally.

Recently the application of the natural filler was increased in order to avoid environmental issues. In this study, SBG (Sugarcane Baggage) was employed while fabrication of woven glass fiber composite. Regarding this vacuum assist resin infusion manufacturing (VARI) process was used to fabricate the composite. Three different weight percentages (5–15%) were used as filler in this study. Furthermore tensile and charpy impact test was conducted on the specimen and compared with the original. The damage mode of the specimen was monitored through an acoustic emission sensor that was placed at the specimen while tensile testing. Four different damage modes were discovered through non-destructive testing that is matrix crack, debonding, delamination and fiber breakage.

The aim of this paper is to investigate an artificial neural network-based approach to determine the chatter stability limit of a milling process with a variable pitch cutter. The variable pitch cutter provides an advantage over the uniform pitch cutter as it shows increased stability behavior in a small range of spindle speed and depth of cut. The training data for the neural network is obtained by time domain simulations for a given combination of cutting parameters like cutting coefficients, feed and machine dynamic parameters like stiffness and damping. This data is fed to the multi-layer perceptron neural network to solve a classification problem using the scaled conjugate gradient method. The network performance is compared for several network architectures and the best combination is chosen. Once trained, the neural network is able to predict the stability of any given cutting condition with an accuracy of 99%.

In this present research work effect of chromium in ferrous material by using the powder metallurgy technique is been studied in detail. Chromium is added to iron matrix in various proportions of 2%Cr, 4%Cr, 6%Cr, and 8%Cr and the remaining is Fe powder. First challenge was to produce these metal matrix composites by using the powder metallurgy technique, we also added zinc stearate as a binder and die releasing agent. The compaction load is optimized to 160KN by trial-and-error method to get a healthy specimen and the required density is achieved (Mahajan et al. in Indian J Sci Technol 8:101–105, 2015). These compacted green specimens were sintered at 12,000 C to make them hard and useable shape. Once this Fe–Cr metal matrix composite is successfully prepared by using the powder metallurgy technique these composites were tested for Vickers Hardness number and corrosion behaviour and tested under an optical microscope to study on microstructure of the prepared composites (Gurcan and Baker in Wear 188:185–191, 1995). During these tests, it showed that the purest iron specimen produced at 160 KN load and sintered at 12,000 C showed a hardness of 126HV against a 100HV of 6% of Cr in the Fe matrix, that clearly shows that Cr is not contributing much to the hardness of the composites (Yih and Chung in Int J Powder Metall (1986) 31(4):335–340, 1995). Corrosion tests on these sample show that adding Cr to Fe matrix will definitely delay the corrosion to a good extent and microstructure studies revealed that chromium reinforcement in the iron matrix is uniformly distributed and no internal defects are found (Saheb in ARPN J Eng Appl Sci 6:41–46, 2011).

Protrusions are the discontinuities on the surface. It can be sheet joints or control surfaces that cause protrusion. In low speed flow, the boundary layer thickness is higher so that protrusion has a small effect compared to high speeds which have a thin boundary layer. In hypersonic flow, even a small protrusion can cause a severe increment in heat load. As the height and geometry of the protrusion change the effect in the flow field also changes. Heat flux due to protrusion depends on height, shape and inlet conditions. The maximum heat flux occurs on the vertical surface of the protrusion. The maximum heat flux in front of the protrusion depends on the height of the protrusion. The flow separation distance in front of the protrusion is about 3–4 times the protrusion height.

Congenital Talipes Equinovarus (CTEV) or commonly known as clubfoot is a type of deformity present at birth. This deformity involves the baby’s foot twisted out of shape or position. Under clubfoot, the tissues which connect the muscles to the bone (tendons) are short than usual. The deformity may be in one or both feet and is curable easily, even without surgery. Clubfoot usually makes it hard to walk normally, so doctors suggest treating it soon after birth. It can be treated by both methods surgically and non-surgically. As the surgical method is very painful, mostly non-surgical methods are used. As a baby’s bones and joints are incredibly soft and flexible, non-surgical methods can be used in the first week after birth. The existing treatment options include Casting (Poinsettia method), Surgery and Splints. In this research, the focus is on analysing already existing static and dynamic splints by modelling and simulations, studying their mechanism and effect on patients and developing a splint that can be used as a static as well as a dynamic splint and reducing its cost (Mayoclinic, Clubfoot, https://​www.​mayoclinic.​org/​diseases-conditions/​clubfoot/​symptoms-causes/​syc-20350860, 2019).

In this work, experimental validation of position and orientation equations is carried out on a prototype of five degree of freedom robotic manipulator. The experimental setup is fabricated in-house to study the spatial properties of a manipulator and validate the equations obtained from the Denavit–Hartenberg parameters. The results obtained show that for a specific set of theta values, the end effector position and orientation represented by the Cartesian co-ordinate system matches closely both for the mathematical model as well as experimental data. The slight deviation observed may be attributed to fabrication and experimental error.

The influencing parameters like infill density, infill pattern, nozzle temperature and layer height on tensile strength of carbon fiber-reinforced Polylactic Acid (PLA) samples were investigated. PLA along with carbon fiber composite filament is used as a printing material owing to its excellent structural properties. Fused Deposition Modeling (FDM) technique is employed in the present investigation due to its simplicity. Fused Filament Fabrication (FFF) is one of the simplest and most cost-effective printing techniques in the Additive manufacturing process. The different printing parameters are used to develop the tensile samples as per Taguchi’s design of experiments. A L16 orthogonal array was selected from the set of levels and factors in the present investigation. The tensile specimens were printed as per the ASTM D638 testing standard. It has been observed from the results that the most influencing parameter on tensile strength is infill density, and infill pattern layer thickness is having very less influence on tensile strength followed by nozzle temperature. The maximum tensile strength of 61.83 MPa is obtained at a line pattern with 90% of infill density with a layer thickness of 0.05 mm printed with a nozzle temperature of 210 °C.

This study has been done to make a model of Mn and Ni transfer in terms of flux ingredients in submerged arc welding (SAW). The high Mn and Ni are desired in steel up to a certain extent. As it has an impact on the properties of the joint. However, beyond a certain increase, the tensile strength of the joint and ultimate strength of the welds are decreased. Elements transfer to the weld can be governed by the type and constituents of flux and wire composition. This can be done for getting the desirable properties. This study uses the twenty fluxes which are designed by using RSM. The properties of the welds are ensured by the composition of the welds. The flux and consumables also decide the weld metal properties. To study the effect of flux constituents on elements transfer during SAW, the welding parameters have been made constant in this study. The mathematical modelling of manganese and nickel transfer to the weld can predict the weld chemistry, and the desired weld metal properties can be obtained.