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.

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.

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.

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.

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

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.

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 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.

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.

Different techniques are used to obtain approximate solutions for delayed functional differential equations (RFDEs). All these models used the so-called stability lobe diagrams, to choose the maximum axial depth of cut for a given spindle speed associated with a free chatter in machining. In this research paper, the ZOA (Zeroth Order Approximation) and SD (Semi Discretization) methods are explained, developed and used to obtain the stability lobe diagrams for a milling cutting system with two degree of freedom, in high speed machining case.

The research work reported in this paper focuses on introduces a fully STEP-compliant CNC by putting forward an interpolation algorithm for Non Uniform Rational Basic spline (NURBS) curve system for rough milling tool paths with an aim to solve the problems faced by the current CNC systems. The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that are difficult to machine because of its twisted blades. The research is based on the premise that a STEP-NC program can document Dzgenericdz manufacturing information for an impeller. This way, a STEP-NC program can be made machine-independent and has an advantage over the conventional G-code based NC program that is always generated for a specific CNC machine. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. A key feature of the system is the use of STEPNC data model (ISO 14649-10: 2003; ISO 10303-238, 238: 2003), which enables more design information (e.g. geometry, workpiece information and tolerances) to be incorporated both prior to and during machining processes. The relevant algorithm for the curve was simulated in CAM software. The results have shown that the algorithm for rough milling is feasible and effective.

The research work reported in this paper focuses on introduces a fully STEP-compliant CNC by putting forward an interpolation algorithm for Non Uniform Rational Basic spline (NURBS) curve system for rough milling tool paths with an aim to solve the problems faced by the current CNC systems. The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that are difficult to machine because of its twisted blades. The research is based on the premise that a STEP-NC program can document Dzgenericdz manufacturing information for an impeller. This way, a STEP-NC program can be made machine-independent and has an advantage over the conventional G-code based NC program that is always generated for a specific CNC machine. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. A key feature of the system is the use of STEPNC data model (ISO 14649-10: 2003; ISO 10303-238, 238: 2003), which enables more design information (e.g. geometry, workpiece information and tolerances) to be incorporated both prior to and during machining processes. The relevant algorithm for the curve was simulated in CAM software. The results have shown that the algorithm for rough milling is feasible and effective.

The research work reported in this paper focuses on introduces a fully STEP-compliant CNC by putting forward an interpolation algorithm for Non Uniform Rational Basic spline (NURBS) curve system for rough milling tool paths with an aim to solve the problems faced by the current CNC systems. The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that are difficult to machine because of its twisted blades. The research is based on the premise that a STEP-NC program can document Dzgenericdz manufacturing information for an impeller. This way, a STEP-NC program can be made machine-independent and has an advantage over the conventional G-code based NC program that is always generated for a specific CNC machine. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. A key feature of the system is the use of STEPNC data model (ISO 14649-10: 2003; ISO 10303-238, 238: 2003), which enables more design information (e.g. geometry, workpiece information and tolerances) to be incorporated both prior to and during machining processes. The relevant algorithm for the curve was simulated in CAM software. The results have shown that the algorithm for rough milling is feasible and effective.

The research work reported in this paper focuses on introduces a fully STEP-compliant CNC by putting forward an interpolation algorithm for Non Uniform Rational Basic spline (NURBS) curve system for rough milling tool paths with an aim to solve the problems faced by the current CNC systems. The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that are difficult to machine because of its twisted blades. The research is based on the premise that a STEP-NC program can document Dzgenericdz manufacturing information for an impeller. This way, a STEP-NC program can be made machine-independent and has an advantage over the conventional G-code based NC program that is always generated for a specific CNC machine. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. A key feature of the system is the use of STEPNC data model (ISO 14649-10: 2003; ISO 10303-238, 238: 2003), which enables more design information (e.g. geometry, workpiece information and tolerances) to be incorporated both prior to and during machining processes. The relevant algorithm for the curve was simulated in CAM software. The results have shown that the algorithm for rough milling is feasible and effective.

The research work reported in this paper focuses on introduces a fully STEP-compliant CNC by putting forward an interpolation algorithm for Non Uniform Rational Basic spline (NURBS) curve system for rough milling tool paths with an aim to solve the problems faced by the current CNC systems. The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that are difficult to machine because of its twisted blades. The research is based on the premise that a STEP-NC program can document Dzgenericdz manufacturing information for an impeller. This way, a STEP-NC program can be made machine-independent and has an advantage over the conventional G-code based NC program that is always generated for a specific CNC machine. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. A key feature of the system is the use of STEPNC data model (ISO 14649-10: 2003; ISO 10303-238, 238: 2003), which enables more design information (e.g. geometry, workpiece information and tolerances) to be incorporated both prior to and during machining processes. The relevant algorithm for the curve was simulated in CAM software. The results have shown that the algorithm for rough milling is feasible and effective.

L’assemblage des plaques stratifiées ou des structures hybrides  composites/métalliques est un passage essentiel dans la réalisation des structures aéronautiques et aérospatiales. Il est alors nécessaire d’effectuer des opérations de perçage dans les plaques stratifiées. L’arrangement des fibres et leur orientation permettent de modifier les propriétés mécaniques du pli. Le concepteur peut ainsi modifier à volonté la résistance mécanique des plaques stratifiées en jouant sur l’orientation des fibres et la séquence d’empilement. Il nous paraît indispensable de prendre en compte l’effet des trous et l’orientation des fibres sur l’ensemble des mécanismes de ruine. Dans ce travail nous avons mis en évidence l’effet de l’orientation des fibres dans chaque pli et le choix de la séquence d’empilement sur la résistance à la rupture des plaques stratifiées multitrous en matériau composite carbone/époxyde sollicitées en traction.

his paper presents a combined experimental and theoretical investigation and proposes a mechanical load modeling of a multidirectional layer CFRP drilling to avoid fibers delamination by a better choice of their orientations. A first step consists in working with unidirectional CFRP to correlate cutting mode (opening, shear and bending) with force level depending on the angular tool position. The discretisation of the cutting edge is employed to know the exact contribution of each elementary part of the edge, resulting in a complete drill operation modeling (tip penetration, full engagement and exit). A second step consists in using this unidirectional approach to model a multidirectional layer CFRP drilling. In this case, layers are cut simultaneously which induce brutal mechanical load variation. A summation method is used to estimate the force level depending on fiber arrangement. Optimal orientation combinations are underlined by this approach, in order to improve the CFRP design, by considering the manufacturing concerns.

The machining of the complex forms is a characteristic of moulds and matrices manufacturing. Owing to the fact that these forms became increasingly complicated, the production of moulds and matrices require tolerances which are particularly severe. One of the principal objectives to be reached is the precision of machining and the improvement of the micro geometrical state of machined surfaces, for the minimization of polishing operations after machining which still necessary to obtain a good finished part, which is required by the car industry and the aeronautic industry. To reach these goals, it is important to choose a tool which fulfils the requirements of a machining which could be carried out in various orientations. This will make possible the machining of complex forms by using a milling machine with several axes. Among the tools allowing the realization of these complex forms, there is the ball-end mill. The goal of this work is to study the geometry of the mill's spherical part, in order to determine the contact zones between the part of complex form and the tool which is following a trajectory in space.

We have determined in which conditions we have a regenerative vibration cases (chatter). We have used the simulation of a machining system dynamic behaviour. A cutting force law was obtained by an indirect method, by comparing between simulation results and experimental ones.