Designing and manufacturing replacement cancellous bone structures by lattice structures and Additive Manufacturing (AM) techniques is an effective method to create lightweight orthopedic implants while ensuring that they are mechanically compatible and their osseointegration ability with the host bone. In this article, we suggest a new design based on three lattice structures from triply periodic minimal surfaces (TPMS) with a different volume porosity to replace cancellous bone based on predicting the mechanical stiffness. To predict the mechanical stiffness, the relationship between the effective modulus of elasticity and different porosity ratios of the lattice structures was determined by using three methods: i) finite element modeling (FEM) simulation, ii) Gibson and Ashby method and iii) a uniaxial compression test after manufacturing the lattice structures by using Fused Filament Fabrication (FFF) Technology. To demonstrate the efficiency of our approach, the comparison of both numerical and experimental results showed that the effect of structure difference and porosity ratio of lattice structures on the mechanical stiffness values effectively match the cancellous bone in terms of elastic modulus and porosity ratio.

The turbine blades are subjected to high operating temperatures and high centrifugal tensile stress due to rotational speeds. The maximum temperature at the inlet of the turbine is currently limited by the resistance of the materials used for the blades. The present paper is focused on the thermo-mechanical behavior of the blade in composite materials with reinforced mast under two different types of loading. The material studied in this work is a composite material, the selected matrix is a technical ceramic which is alumina (aluminum oxide Al2O3) and the reinforcement is carried out by short fibers of high modulus carbon to optimize a percentage of 40% carbon and 60% of ceramics. The simulation was performed numerically by Ansys (Workbench 16.0) software. The comparative analysis was conducted to determine displacements, strains and Von Mises stress of composite material and then compared to other materials such as Titanium Alloy, Stainless Steel Alloy, and Aluminum 2024 Alloy. The results were compared in order to select the material with the best performance in terms of rigidity under thermomechanical stresses. While comparing these materials, it is found that composite material is better suited for high temperature applications. On evaluating the graphs drawn for, strains and displacements, the blade in composite materials reinforced with mast is considered as optimum.

Designing and manufacturing lattice structures with Topology Optimization (TO) and Additive Manufacturing (AM) techniques is a novel method to create light-weight components with promising potential and high design flexibility. This paper proposes a new design of lightweight-graded lattice structures to replace the internal solid volume of the turbine blade to increase its endurance of high thermal stresses effects. The microstructure design of unit cells in a 3D framework is conducted by using the lattice structure topology optimization (LSTO) technique. The role of the LSTO is to find an optimal density distribution of lattice structures in the design space under specific stress constraints and fill the inner solid part of the blade with graded lattice structures. The derived implicit surfaces modelling is used from a triply periodic minimal surfaces (TPMS) to optimize the mechanical performances of lattice structures. Numerical results show the validity of the proposed method. The effectiveness and robustness of the constructed models are analysed by using finite element analysis. The simulation results show that the graded lattice structures in the improved designs have better efficiency in terms of lightweight (33.41–40.32%), stress (25.52–48.55%) and deformation (7.35–19.58%) compared to the initial design.

This work is a study of the elastic fields’ effect (stresses and displacements) caused by dislocations networks at a heterostructure interface of a InAs / GaAs semiconductors thin system in the cases of isotropic and anisotropic elasticity. The numerical study of this type of heterostructure aims to predict the behavior of the interface with respect to these elastic fields satisfying the boundary conditions. The method used is based on a development in Fourier series. The deformation near the dislocation is greater than the other locations far from the dislocation.     

Electrochemical methods, weight loss and surface analysis technique were used to study the effect of glutamic acid on the corrosion of Fe-19Cr stainless steel in 1 M hydrochloric acid solution. Results revealed that the corrosion inhibition of glutamic acid of Fe-19Cr in 1 M HCl was enhanced in the presence of the iodide ions due to synergistic effect. In the absence of KI, the inhibition of Fe-19Cr corrosion by glutamic acid was glutamic acid concentration dependent. Potentiodynamic polarization curves demonstrated that glutamic acid acts as a mixed type inhibitor. Self-Assembled Monolayers of glutamic acid were able to protect stainless steel from corrosion effectively. The adsorption of the inhibitor onto the stainless steel surface follows Langmuir adsorption isotherm. The value of free energy of the adsorption indicated that there is a physical interaction between the glutamic acid and the stainless steel surface.

During turning operations, tool-part-chip contact causes wear to the cutting tool. The objective of this work is to study the wear of the clearance faces of tungsten carbide cutting tools during turning operations. Experimental tests on tool life for dry turning operations were carried out at four different cutting speeds, where the feed rate and the depth of cut are kept at constant values: 0.08 mm/rev for feed rate and 0.5 mm for depth of cut. An analysis of the influence of cutting parameters on the tools wear and consequently tool life (Τ) was presented, then the roughness of the machined surface Ra and the morphology of the chips produced were studied. This study makes it possible to identify that the wear mechanisms and the tool life are strongly linked to the roughness of the machined surfaces and to the morphology of the chips produced during the turning operations.

In this work we present a new biomimetic disc prosthesis imitating the fibroreinforced osmotic, and viscoelastic properties of the biological intervertebral disc (BID). For this, we proposed to study the second-generation biomimetic prosthesis "the M6-C prosthesis" which contains two metal plates, a core and a fiber fabric. First, a 3D model was established, the finite element analysis (FEA) under the ANSYS©2015 was conducted. Secondly, a biomimetic material, the silicone rubber, was compared with the polyethylene to find the material that mimics the behavior of a biological disk. Finally, the analysis of the results found the polymer has the same mechanical properties as the nucleus pulposus, in particular the viscoelastic behaviour compared with that of polyethylene

In this investigation, a new simple triangular strain based membrane element with drilling rotation for 2-D structures analysis is proposed. This new numerical model can be used for linear and dynamic analysis. The triangular element is named SBTE and it has three nodes with three degrees of freedom at each node. The displacements field of this element is based on the assumed functions for the various strains satisfying the compatibility equations. This developed element passed both patch and benchmark tests in the case of bending and shear problems. For the dynamic analysis, lumped mass with implicit/explicit time integration are employed. The obtained numerical results using the developed element converge toward the analytical and numerical solutions in both analyses.

The prediction of machining accuracy of a fiveaxis machine tool is a vital process in precision manufacturing for machining a hard and free form surfaces. This work presents a novel approach for predicting kinematic errors solutions in five-axis machine for trochoidal milling strategy. This approach is based on Artificial Neural Network (ANN) for trochoidal milling machining strategy. We proposed a multi-layer perceptron (MLP) model to find the inverse kinematics solution for a five-axis machine. The data sets for the neural-network model are obtained using kinematics software. The solution of each neural network is estimated using inverse kinematics equation of the machine tool to select the best one. As a result, the Neural Network implementation improves the performance of the learning process. For this, numerical study of trochoidal strategy and experimental results are presented with aims to full milling and to ensure a control of radial engagement. The experimental result shows the efficiency of the method by obtainning the toolpath and the machining possebility of this new type of strategy emerging.

The prediction of machining accuracy of a Five-axis Machine tool is a vital process in precision manufacturing. This work presents a novel approach for predicting kinematic errors solutions in five axis Machine. This approach is based on Artificial Neural Network (ANN) for trochoidal milling machining strategy. We proposed a multi-layer perceptron (MLP) model to find the inverse kinematics solution for a Five-axis Machine Matsuura MX-330. The data sets for the neural-network model is obtained using Matsuura MX-330 kinematics software. The solution of each neural network is estimated using inverse kinematics equation of the Machine tool to select the best one. As a result, the Neural Network implementation improves the performance of the learning process. In this work trochoidal trajectory generation formulation has been developed and simulated using the software Matlab Inc. The main advantage of the trochoidal path is to present a continuous path radius leading the machining process to take place under favorable conditions (no impact, less marking of the part, ...). Obtaining the toolpath is to allow programming of the toolpath according to ISO 6983 (which defines the principles of the G code). For this, numerical study of trochoidal strategy and experimental result are presented with aims to full milling and to ensure a control of radial engagement.

The Hip resurfacing prosthesis is subjected to different stresses resulting from the different positions of the human walk, thereby generating dynamic stresses that vary with time, leading the implant material to fatigue failure. It is important to study the fatigue behavior of the prosthesis material and to ensure its long lifetime. We proposed a new composite material named CF/PA12 composed of carbon fibers with a polyamide 12 resin, whose biocompatibility had been demonstrated in laboratories. In this study, we investigated the static and dynamic behavior at different Gait cycle positions of a Hip resurfacing prosthesis entirely made of new CF/PA12 composite. A fatigue behavior will be deducted by a Finite Element Analysis using the commercial SolidWorks software compatible with the Abaqus finite element code. Static and dynamic analysis were conducted considering normal walking and climbing stairs loading at different Gait cycle percentages of 2, 13, 19, 50 and 63%. The results obtained showed that Hip resurfacing prosthesis fully made of new CF/PA12 composite was very far from fatigue and therefore from failure.

Various ball and socket-type designs of cervical artificial discs are in use or under investigation. All these disc designs claim to restore the normal kinematics of the cervical spine. In this study, we are interested in the cervical prosthesis, which concerns the most sensitive part of the human body, given the movements generated by the head. The goal of this work is to minimize the constraints by numerical shape optimization in the prodisc-C cervical spine prosthesis in order to improve performance and bio-functionality as well as patient relief. Prodisc-C cervical spine prosthesis consists of two cobalt chromium alloy plates and a fixed nucleus. Ultra-high molecular weight polyethylene, on each plate there is a keel to stabilize the prosthesis; this prosthesis allows thee degrees of freedom in rotation. To achieve this goal, a static study was carried out to determine the constraint concentrations on the different components of the prosthesis. Based on the biomechanical behaviour of the spine discs, we totally fixed the lower metal plate; a vertical load of 73.6 N to simulate the weight of the head was applied to the superior metallic endplate. After a static study on this prosthesis, using a finite element model, we noticed that the concentration of the Von-Mises stress is concentrated on the peripheral edge core and the concave articulating surface of the superior metallic endplate the numerical. We use the module optimization for 3D SolidWorks for optimize our design, based on the criteria of minimizing stress value. Shape optimization concluded to minimize the equivalent stress value on both joint surface (concave and convex) from 11.3 MPa to 9.1MPa corresponding to a percentage decrease of 19.4% from the original geometry. We conclude that despite the fact that maximum Von Mises stresses are higher in the case of the dynamic load, remains that they are weak. Which is an advantage for the durability of the prosthesis and-also for the bone, because a low stress concentration on the prosthesis will reduce stress concentration generated by the implant on the bone, therefore its risk of fracture reduces.

In contour milling, to render the machining process more automated with significant productivity without remaining material after machining, a new recovery coefficient was developed. The coefficient was inserted in the computation of contour parallel tool paths to fix the radial depth of cut in the way to ensure an optimized overlap area between the passes in the corners, without residuals. Thus, this parameter, which has been earlier inserted by the user, is now being independent and is implemented automatically from the input data of the contour shape of the pocket. In order to prove the effectiveness of the present approach, a detailed comparison with the classical methods found in the literature we also performed. The results clearly show that the new method removes the residuals efficiently in an automatic way and minimizes the toolpath length respect to the other methods. Furthermore, this proposed approach can easily be worked on the actual machine tool.

In the present work, (Cu-Sn, Cu-Co) based alloys with different compositions have been obtained by using powder metallurgy (PM). These alloys were created with the purpose of increasing mechanical and structural properties of the industrial parts. The compacts are made according to the sintering manufacturing method, the uniaxial compressed cold samples. Metallographic characterizations, hardness and density measurements were carried out in order to study the influence of the addition of tin and cobalt, the variation of the compaction pressure and the sintering temperature on the finishing product. It has been proved that the addition of tin and cobalt to a copper powder mixture increase the properties of the sintered parts.

The aim of this review is to present and discuss the research work reported in the literature on the use of glutamic acid and its derivatives as corrosion inhibitors for metals in different aggressive solutions. Mass loss and electrochemical techniques were among the most often used techniques to evaluate the corrosion inhibition efficiency of the used inhibitor. Glutamic acid can act as an efficient corrosion inhibitor, but it can in other cases show an opposite effect, which accelerates the corrosion process; all depend on the experimental conditions. Highest values of inhibition efficiency were obtained in the presence of ions as Zn²⁺ and ions halides. Glutamic acid derivatives have shown a good ability to use it as an effective corrosion inhibitor for metal in an acidic solution. The development of computational modeling helps to design new glutamic acid derivatives and to understand the inhibition mechanism of those compounds.