Mokhtar Bourdim - Academia.edu (original) (raw)

Papers by Mokhtar Bourdim

International Review of Mechanical Engineering-IREME, Nov 30, 2016

Rolling bearings are the most fragile components of rotating machines. To avoid unforeseen stoppa... more Rolling bearings are the most fragile components of rotating machines. To avoid unforeseen stoppages and expensive production, it must then continuously monitor the condition of the bearings, and "stalk" all faults signs: an unusual noise, abnormal vibration, temperature rise, and so on. For this, these are not techniques that are missing. Conventional vibration analysis methods (envelope detection, spectre analysis, crest factor, etc.) to more specific techniques such as shock wave, they can detect faults at an early stage more or less and sometimes to determine the exact origin. In this approach we try to show the influence of operating conditions of a rolling on his life, and to award the method of real service to follow for assessing the remaining duration of survival for many supply and provide the judgments of each rotating machine in advance.

Periodica Polytechnica Mechanical Engineering, Jun 7, 2021

An automobile brake disc brought into contact with the pads, mechanical stresses are imposed on t... more An automobile brake disc brought into contact with the pads, mechanical stresses are imposed on the contact surface. These stresses can cause degradation by fatigue, rupture, wear, propagation of cracks. Modeling the numerical results makes it possible to recognize this damage in order to improve the braking system, extend its service life, reduce the cost of maintenance and make it more reliable. The aim of our study concerns modeling and numerical simulation using ANSYS 14.5 software based on the finite element method under the influence of certain essential parameters on the braking behavior of the torque as a function of geometric parameters, properties mechanical, boundary conditions, type of loading applied, type of materials chosen and type of analysis carried out in braking torques (ventilated drilled disc / pads and ventilated grooved disc / pads), upon contact with a disc in rotation with a plate which represents the friction body on the disc. The behavior of the torque during braking was analyzed in terms of stresses and deformations, and displacements, the comparison between the two types of discs was also discussed.

Identification of nonlinear metal cutting dynamics with respect to machine tool response is impor... more Identification of nonlinear metal cutting dynamics with respect to machine tool response is important for predicting the occurrence of chatter vibration onset (limit of stability). The present paper deals with constitutive modelling of nonlinear metal cutting dynamics with respect to machine tool response. An adopted approach to predict the occurrence of threshold of chatter vibration from the view point of energy transfer in regenerative chatter is to use an analytical formulation which is concerned with the analysis of chatter vibration. Results of this investigation reveal, that machining process develop some energy which is absorbed by the considering structure. The limit of chatter vibration is achieved only when the energy received by the vibrating process is exactly equal to the energy dissipated by the structural damping. The relationship between the oscillating cutting forces and tool vibration is developed. The present analysis reveals that this relationship exhibits an active hysteresis which is proportional to the square of vibration amplitude, and both transmitted and dissipated energies are represented by parabolic curves. The present work reveals that the amplitude, at which the work changes sign, corresponds to the onset of stability. In other words, when chatter vibration (instability) occurs its amplitude is greater than the critical value. In this case, there is a phase lead between cutting force and tool motion. Experimental investigation was conducted to demonstrate the efficacy of this energetic approach.

Advances in Mechanical Engineering, Apr 1, 2017

This paper deals with analyzes of the influence of the perpendicularity of the spindle of the mil... more This paper deals with analyzes of the influence of the perpendicularity of the spindle of the milling machine on the machined surface. This is part of the geometric errors of machine tools and in a direct manner constitutes a defect on the quality of the workpiece. Therefore, the surface roughness is particularly sensitive to the cutting speed, the feed rate, round of teeth default, the tool tip radius and the cutter teeth number. This article examines the characteristics of the surface topography of steel parts, in finishing machining using milling cutters. The study is conducted by computer simulation tests and experimental part using surface condition monitoring instruments, taking into consideration the round teeth default. The variation of the inclination of the spindle of the milling machine in three positions (90°+ 30#, 90°, and 90°-30#) shows a good agreement between the simulation and the experimental results for sharp and moderately worn tools. Similarly, this study showed that the presented model could thus be integrated into systems computer-aided design and computer-aided manufacturing. Finally, the physical and statistical parameters of roughness during milling at position 90°confirmed that, when the defect of the perpendicularity is eliminated to the maximum, the best surface conditions are obtained.

Advances in Production Engineering & Management, Jun 15, 2012

This paper presents and describes the design, manufacturing, calibration and performance of a uni... more This paper presents and describes the design, manufacturing, calibration and performance of a universal cutting dynamometer based on the principle of extensometer strain gage techniques. The device developed in this paper was designed and calibrated for measuring separately components forces developed during turning, drilling and milling operations. Its design is carried out according to the two principal criteria which are in contradictory matters such as sensitivity and rigidity. It consists principally of two circular rings, one allowing its fixation on the tables of the three type of machine tools, and the other one is machined so that the complete dynamometer can be attached to machines tables. The strain gages are then cemented on the parts of the dynamometer where the deformations (traction, compression and torsion) are maximum. The gages are connected in the form of a full wheatstone bridge, any unbalance in which would indicate the thrust force ant the torque providing maximum sensitivity and complete temperature compensation. The disposition and the connection of the strain gages in complete Wheastone bridge are carried out according to the force component to measure while taking account of the interactions between the three directions and the compensation of the effect of the temperature. The reading is indicated on standard indicator of constraints B & K 1526. Some experimental measurements of components forces and torque in the drilling process obtained with the described dynamometer are presented and compared with available data given by other research worker.

HAL (Le Centre pour la Communication Scientifique Directe), Aug 26, 2013

The aim of this paper is the determination of a control model of involute gears with respect to θ... more The aim of this paper is the determination of a control model of involute gears with respect to θ m , based on the application of neural networks. Neural networks are appropriate for the diagnosis of complex systems and control because of its ability to handle data input and output without the need for analytical details of the system. First, we must know the angle to wipe the edge of a tooth surface, with. We acquire the points entered in standard path of the tooth. Then we execute the neurons on these points to determine the weights is the step that is called learning networks. That last request 94.41s. So it becomes all models of the gear standard with the same characteristics. So, if we wanted a control gear of the same module, it will be only a few points seized by CMMs. On the other hand, is looking for the model of the wheel to control the proper starting weight calculated from previous models. His duration of control esteem 1.6 s. Moreover, we can evaluate the deformities of gear compared to model neurons and the points entered. Finally, the role of this work is the set of model control equipment; we know it contains multiple paths and multivariate parametric complex. So, it's not easy have the control. However, ours, we can know all the deformities of the gears in about 1.60s instead of 45 min at least by the test bench, accordingly, we can say that we achieve the automation of gear control.

This paper presents a theoretical and experimental investigation into the stability of a cantilev... more This paper presents a theoretical and experimental investigation into the stability of a cantilever boring bar under regenerative cutting conditions. As this cutting tool is flexible, the regenerative chatter variation often occurs and causes several problems which not only limits productivity of cutting process, but also affects surface finish, cause premature tool failure and reduce dimensional accuracy of the machined part. Its prediction is then important as a guidance to the machine tool user for an optimal selection of cutting conditions, resulting in maximum chip removal rate without this undesirable self excited vibration. While boring, the chatter vibration may occur in the through-thickness direction of workpiece. The vibration changes removal cross section of workpiece in the present cut and furthermore in the next cut. This change in cross section produces dynamic cutting force variation. When this dynamic cutting force excites the mechanical structure and grows up the previous vibration, this closed-loop instability leads to the regenerative chatter vibration. The boring bar is modeled at the tool point by a mass, spring and damper system free to move in the two mutually perpendicular directions. The solution of the non uniform equilibrium equation of motion of the cutting tool (boring bar) yielded a characteristic equation in a form of a fourth order polynomial with complex and variable coefficients. The stability of this complex polynomial is based on the Nyquist criterion. This allowed us to plot graphs of stability which indicated clearly that the cutting condition has a decisive influence on the generation of chatter vibrations leading to the instability of cutting. The developed model is verified by cutting experiments, and it is expected that the computed results are in good agreement with the experimental one, and the analytical model is useful to optimize the cutting conditions for highly efficient cutting process.

Materials Today Communications

International Journal of Energy and Environment

Turning is one of the most widely used machining processes in the mechanical engineering industry... more Turning is one of the most widely used machining processes in the mechanical engineering industry. Thus, the choice of optimal cutting parameters (cutting speed, feed and depth of cut) is very important in order to ensure a better surface condition of the machined parts and the life of the cutting tools, which requires great relationship with the wear of the tool-part interface. The result of a good choice of cutting conditions can be seen by a reduction in this wear. During machining, the geometric shape and the physical state of the tool are modified by the combined action of the cutting forces and by the temperature reached by the cutting edge. These modifications which gradually increase with the duration of machining are commonly grouped under the term wear of the tool. They appear on the active part of the tool. In this work, we propose an optimization method allowing determining a mathematical model of the wear and tear by applying the experiment plan. This model highlights t...

International Journal of Materials, 2022

The present work, constituted a theoretical study of the phenomenon of the electric conductivity ... more The present work, constituted a theoretical study of the phenomenon of the electric conductivity of composite conducting polymers. Generally, the polymers are used as electrical insulators. The incorporation of conducting loads in an insulating polymeric matrix makes it possible to obtain materials having at the same time a high electric conductivity and a low density. These materials offer a great number of applications such as the electromagnetic shielding, the protection of metals against corrosion, the adhesives conducting, the connectors, the sensors, etc. The prediction and modelling of the electrical behaviour of these composite materials are needed for the choice of their scope and could therefore reduce the onerous experimental work and the cost of production through an optimized design. We carried out a theoretical study. To make this study, we are based on experimental results existing in the specialized literature and we build a new ideal model which describes the variat...

This paper presents a theoretical and experimental investigation into the stability of a cantilev... more This paper presents a theoretical and experimental investigation into the stability of a cantilever boring bar under regenerative cutting conditions. As this cutting tool is flexible, the regenerative chatter variation often occurs and causes several problems which not only limits productivity of cutting process, but also affects surface finish, cause premature tool failure and reduce dimensional accuracy of the machined part. Its prediction is then important as a guidance to the machine tool user for an optimal selection of cutting conditions, resulting in maximum chip removal rate without this undesirable self excited vibration. While boring, the chatter vibration may occur in the through-thickness direction of workpiece. The vibration changes removal cross section of workpiece in the present cut and furthermore in the next cut. This change in cross section produces dynamic cutting force variation. When this dynamic cutting force excites the mechanical structure and grows up the p...

The performance and success of cemented total hip arthroplasty is related to the stress fields in ... more The performance and success of cemented total hip arthroplasty is related to the stress fields in the cement mantle due to the loading caused by patient activities. To do this, a three dimensional linear elastic model was developed to investigate the intensity and distribution of equivalent stress in the bone cement (PMMA) between the microvoids. This analysis is made according to several parameters such as the size of the microvoids defects, its direction of the arrangement, its location in the seat of the stress concentration and the volume fraction of the microvoids (the microvoid-microvoid interdistance).

This paper presents the modeling, design, and simulation of an adaptive neuro fuzzy inference str... more This paper presents the modeling, design, and simulation of an adaptive neuro fuzzy inference strategy (ANFIS) for controlling the speed of the Double Star induction Machine, the machine is fed by a five-level inverter. Analytical solutions of Pulse Width Modulation (PWM) strategies for multilevel Neutral Point Clamped (NPC) are presented. Double star Induction motor is characterized by highly non-linear, complex and time-varying dynamics and inaccessibility of some of the states and outputs for measurements. Hence it can be considered as a challenging engineering problem in the industrial sector. Various advanced control techniques has been devised by various researchers across the world. Some of them are based on the neuro-fuzzy techniques (ANFIS). The main advantage of designing the ANFIS coordination scheme is to control the speed of the DSIM to increase the dynamic performance, to provide good stabilization. To show the effectiveness of our scheme, the proposed method was simul...

The aim of this paper is the determination of a control model of involute gears with respect to θ... more The aim of this paper is the determination of a control model of involute gears with respect to θm, based on the application of neural networks. Neural networks are appropriate for the diagnosis of complex systems and control because of its ability to handle data input and output without the need for analytical details of the system. First, we must know the angle to wipe the edge of a tooth surface, with. We acquire the points entered in standard path of the tooth. Then we execute the neurons on these points to determine the weights is the step that is called learning networks. That last request 94.41s. So it becomes all models of the gear standard with the same characteristics. So, if we wanted a control gear of the same module, it will be only a few points seized by CMMs. On the other hand, is looking for the model of the wheel to control the proper starting weight calculated from previous models. His duration of control esteem 1.6 s. Moreover, we can evaluate the deformities of g...

In this work, an experimental study was conducted with the objective of achieving a microscopic c... more In this work, an experimental study was conducted with the objective of achieving a microscopic characterization of samples aged of wastewater and sewer pipes HDPE reinforced with glass fibers in a H2SO4 solution with different concentrations, using the Microscope scanning electron (SEM). The microscopic results show that degradation at the fiber / matrix interface worsens as the increase of the concentration of H2SO4.

Identification of nonlinear metal cutting dynamics with respect to machine tool response is impor... more Identification of nonlinear metal cutting dynamics with respect to machine tool response is important for predicting the occurrence of chatter vibration onset (limit of stability). The present paper deals with constitutive modelling of nonlinear metal cutting dynamics with respect to machine tool response. An adopted approach to predict the occurrence of threshold of chatter vibration from the view point of energy transfer in regenerative chatter is to use an analytical formulation which is concerned with the analysis of chatter vibration. Results of this investigation reveal, that machining process develop some energy which is absorbed by the considering structure. The limit of chatter vibration is achieved only when the energy received by the vibrating process is exactly equal to the energy dissipated by the structural damping. The relationship between the oscillating cutting forces and tool vibration is developed. The present analysis reveals that this relationship exhibits an ac...

SPIN, 2020

Full-Heuslers are a group of materials that have repeatedly attracted the curiosity of scientists... more Full-Heuslers are a group of materials that have repeatedly attracted the curiosity of scientists and researchers, especially for their use in the field of spintronics. In this work, we undertook a study on the structural, elastic, electronic, magnetic and thermodynamic properties of the full-Heusler Mn2OsGe alloy using the calculations of the first principles. Two approximations are used: the generalized approximation of the Perdew–Burke–Ernzerhof GGA–PBE gradient for electron-correlation exchange and the new modified Tran-Blaha form of the modified Becke-Johnson mBJ–GGA-PBE potential. As important results, we found that the compound Mn2OsGe is stable in the CuHg2Ti structure; on the other hand, we could also verify its mechanical stability at zero temperature and pressure. For the calculation of the electronic properties, we were able to determine the half-metallic ferrimagnetic character of our compound, which exhibits a metallic behavior in the state of the majority spins, and a...

MOJ Applied Bionics and Biomechanics, 2017

The results of a quasi-static analysis of the finite elements and the modeling of the mechanical ... more The results of a quasi-static analysis of the finite elements and the modeling of the mechanical (thermo-viscoplastic) behavior of the material are presented using the constitutive law of Johnson-Cook. This law of behavior being pre-integrated into the ABAQUS code. We were particularly interested in the influence of the mechanical behavior and the nature of the target material on its response to the impacter which is supposed to be rigid.

International Review of Mechanical Engineering-IREME, Nov 30, 2016

Rolling bearings are the most fragile components of rotating machines. To avoid unforeseen stoppa... more Rolling bearings are the most fragile components of rotating machines. To avoid unforeseen stoppages and expensive production, it must then continuously monitor the condition of the bearings, and "stalk" all faults signs: an unusual noise, abnormal vibration, temperature rise, and so on. For this, these are not techniques that are missing. Conventional vibration analysis methods (envelope detection, spectre analysis, crest factor, etc.) to more specific techniques such as shock wave, they can detect faults at an early stage more or less and sometimes to determine the exact origin. In this approach we try to show the influence of operating conditions of a rolling on his life, and to award the method of real service to follow for assessing the remaining duration of survival for many supply and provide the judgments of each rotating machine in advance.

Periodica Polytechnica Mechanical Engineering, Jun 7, 2021

An automobile brake disc brought into contact with the pads, mechanical stresses are imposed on t... more An automobile brake disc brought into contact with the pads, mechanical stresses are imposed on the contact surface. These stresses can cause degradation by fatigue, rupture, wear, propagation of cracks. Modeling the numerical results makes it possible to recognize this damage in order to improve the braking system, extend its service life, reduce the cost of maintenance and make it more reliable. The aim of our study concerns modeling and numerical simulation using ANSYS 14.5 software based on the finite element method under the influence of certain essential parameters on the braking behavior of the torque as a function of geometric parameters, properties mechanical, boundary conditions, type of loading applied, type of materials chosen and type of analysis carried out in braking torques (ventilated drilled disc / pads and ventilated grooved disc / pads), upon contact with a disc in rotation with a plate which represents the friction body on the disc. The behavior of the torque during braking was analyzed in terms of stresses and deformations, and displacements, the comparison between the two types of discs was also discussed.

Identification of nonlinear metal cutting dynamics with respect to machine tool response is impor... more Identification of nonlinear metal cutting dynamics with respect to machine tool response is important for predicting the occurrence of chatter vibration onset (limit of stability). The present paper deals with constitutive modelling of nonlinear metal cutting dynamics with respect to machine tool response. An adopted approach to predict the occurrence of threshold of chatter vibration from the view point of energy transfer in regenerative chatter is to use an analytical formulation which is concerned with the analysis of chatter vibration. Results of this investigation reveal, that machining process develop some energy which is absorbed by the considering structure. The limit of chatter vibration is achieved only when the energy received by the vibrating process is exactly equal to the energy dissipated by the structural damping. The relationship between the oscillating cutting forces and tool vibration is developed. The present analysis reveals that this relationship exhibits an active hysteresis which is proportional to the square of vibration amplitude, and both transmitted and dissipated energies are represented by parabolic curves. The present work reveals that the amplitude, at which the work changes sign, corresponds to the onset of stability. In other words, when chatter vibration (instability) occurs its amplitude is greater than the critical value. In this case, there is a phase lead between cutting force and tool motion. Experimental investigation was conducted to demonstrate the efficacy of this energetic approach.

Advances in Mechanical Engineering, Apr 1, 2017

This paper deals with analyzes of the influence of the perpendicularity of the spindle of the mil... more This paper deals with analyzes of the influence of the perpendicularity of the spindle of the milling machine on the machined surface. This is part of the geometric errors of machine tools and in a direct manner constitutes a defect on the quality of the workpiece. Therefore, the surface roughness is particularly sensitive to the cutting speed, the feed rate, round of teeth default, the tool tip radius and the cutter teeth number. This article examines the characteristics of the surface topography of steel parts, in finishing machining using milling cutters. The study is conducted by computer simulation tests and experimental part using surface condition monitoring instruments, taking into consideration the round teeth default. The variation of the inclination of the spindle of the milling machine in three positions (90°+ 30#, 90°, and 90°-30#) shows a good agreement between the simulation and the experimental results for sharp and moderately worn tools. Similarly, this study showed that the presented model could thus be integrated into systems computer-aided design and computer-aided manufacturing. Finally, the physical and statistical parameters of roughness during milling at position 90°confirmed that, when the defect of the perpendicularity is eliminated to the maximum, the best surface conditions are obtained.

Advances in Production Engineering & Management, Jun 15, 2012

This paper presents and describes the design, manufacturing, calibration and performance of a uni... more This paper presents and describes the design, manufacturing, calibration and performance of a universal cutting dynamometer based on the principle of extensometer strain gage techniques. The device developed in this paper was designed and calibrated for measuring separately components forces developed during turning, drilling and milling operations. Its design is carried out according to the two principal criteria which are in contradictory matters such as sensitivity and rigidity. It consists principally of two circular rings, one allowing its fixation on the tables of the three type of machine tools, and the other one is machined so that the complete dynamometer can be attached to machines tables. The strain gages are then cemented on the parts of the dynamometer where the deformations (traction, compression and torsion) are maximum. The gages are connected in the form of a full wheatstone bridge, any unbalance in which would indicate the thrust force ant the torque providing maximum sensitivity and complete temperature compensation. The disposition and the connection of the strain gages in complete Wheastone bridge are carried out according to the force component to measure while taking account of the interactions between the three directions and the compensation of the effect of the temperature. The reading is indicated on standard indicator of constraints B & K 1526. Some experimental measurements of components forces and torque in the drilling process obtained with the described dynamometer are presented and compared with available data given by other research worker.

HAL (Le Centre pour la Communication Scientifique Directe), Aug 26, 2013

The aim of this paper is the determination of a control model of involute gears with respect to θ... more The aim of this paper is the determination of a control model of involute gears with respect to θ m , based on the application of neural networks. Neural networks are appropriate for the diagnosis of complex systems and control because of its ability to handle data input and output without the need for analytical details of the system. First, we must know the angle to wipe the edge of a tooth surface, with. We acquire the points entered in standard path of the tooth. Then we execute the neurons on these points to determine the weights is the step that is called learning networks. That last request 94.41s. So it becomes all models of the gear standard with the same characteristics. So, if we wanted a control gear of the same module, it will be only a few points seized by CMMs. On the other hand, is looking for the model of the wheel to control the proper starting weight calculated from previous models. His duration of control esteem 1.6 s. Moreover, we can evaluate the deformities of gear compared to model neurons and the points entered. Finally, the role of this work is the set of model control equipment; we know it contains multiple paths and multivariate parametric complex. So, it's not easy have the control. However, ours, we can know all the deformities of the gears in about 1.60s instead of 45 min at least by the test bench, accordingly, we can say that we achieve the automation of gear control.

This paper presents a theoretical and experimental investigation into the stability of a cantilev... more This paper presents a theoretical and experimental investigation into the stability of a cantilever boring bar under regenerative cutting conditions. As this cutting tool is flexible, the regenerative chatter variation often occurs and causes several problems which not only limits productivity of cutting process, but also affects surface finish, cause premature tool failure and reduce dimensional accuracy of the machined part. Its prediction is then important as a guidance to the machine tool user for an optimal selection of cutting conditions, resulting in maximum chip removal rate without this undesirable self excited vibration. While boring, the chatter vibration may occur in the through-thickness direction of workpiece. The vibration changes removal cross section of workpiece in the present cut and furthermore in the next cut. This change in cross section produces dynamic cutting force variation. When this dynamic cutting force excites the mechanical structure and grows up the previous vibration, this closed-loop instability leads to the regenerative chatter vibration. The boring bar is modeled at the tool point by a mass, spring and damper system free to move in the two mutually perpendicular directions. The solution of the non uniform equilibrium equation of motion of the cutting tool (boring bar) yielded a characteristic equation in a form of a fourth order polynomial with complex and variable coefficients. The stability of this complex polynomial is based on the Nyquist criterion. This allowed us to plot graphs of stability which indicated clearly that the cutting condition has a decisive influence on the generation of chatter vibrations leading to the instability of cutting. The developed model is verified by cutting experiments, and it is expected that the computed results are in good agreement with the experimental one, and the analytical model is useful to optimize the cutting conditions for highly efficient cutting process.

Materials Today Communications

International Journal of Energy and Environment

Turning is one of the most widely used machining processes in the mechanical engineering industry... more Turning is one of the most widely used machining processes in the mechanical engineering industry. Thus, the choice of optimal cutting parameters (cutting speed, feed and depth of cut) is very important in order to ensure a better surface condition of the machined parts and the life of the cutting tools, which requires great relationship with the wear of the tool-part interface. The result of a good choice of cutting conditions can be seen by a reduction in this wear. During machining, the geometric shape and the physical state of the tool are modified by the combined action of the cutting forces and by the temperature reached by the cutting edge. These modifications which gradually increase with the duration of machining are commonly grouped under the term wear of the tool. They appear on the active part of the tool. In this work, we propose an optimization method allowing determining a mathematical model of the wear and tear by applying the experiment plan. This model highlights t...

International Journal of Materials, 2022

The present work, constituted a theoretical study of the phenomenon of the electric conductivity ... more The present work, constituted a theoretical study of the phenomenon of the electric conductivity of composite conducting polymers. Generally, the polymers are used as electrical insulators. The incorporation of conducting loads in an insulating polymeric matrix makes it possible to obtain materials having at the same time a high electric conductivity and a low density. These materials offer a great number of applications such as the electromagnetic shielding, the protection of metals against corrosion, the adhesives conducting, the connectors, the sensors, etc. The prediction and modelling of the electrical behaviour of these composite materials are needed for the choice of their scope and could therefore reduce the onerous experimental work and the cost of production through an optimized design. We carried out a theoretical study. To make this study, we are based on experimental results existing in the specialized literature and we build a new ideal model which describes the variat...

This paper presents a theoretical and experimental investigation into the stability of a cantilev... more This paper presents a theoretical and experimental investigation into the stability of a cantilever boring bar under regenerative cutting conditions. As this cutting tool is flexible, the regenerative chatter variation often occurs and causes several problems which not only limits productivity of cutting process, but also affects surface finish, cause premature tool failure and reduce dimensional accuracy of the machined part. Its prediction is then important as a guidance to the machine tool user for an optimal selection of cutting conditions, resulting in maximum chip removal rate without this undesirable self excited vibration. While boring, the chatter vibration may occur in the through-thickness direction of workpiece. The vibration changes removal cross section of workpiece in the present cut and furthermore in the next cut. This change in cross section produces dynamic cutting force variation. When this dynamic cutting force excites the mechanical structure and grows up the p...

The performance and success of cemented total hip arthroplasty is related to the stress fields in ... more The performance and success of cemented total hip arthroplasty is related to the stress fields in the cement mantle due to the loading caused by patient activities. To do this, a three dimensional linear elastic model was developed to investigate the intensity and distribution of equivalent stress in the bone cement (PMMA) between the microvoids. This analysis is made according to several parameters such as the size of the microvoids defects, its direction of the arrangement, its location in the seat of the stress concentration and the volume fraction of the microvoids (the microvoid-microvoid interdistance).

This paper presents the modeling, design, and simulation of an adaptive neuro fuzzy inference str... more This paper presents the modeling, design, and simulation of an adaptive neuro fuzzy inference strategy (ANFIS) for controlling the speed of the Double Star induction Machine, the machine is fed by a five-level inverter. Analytical solutions of Pulse Width Modulation (PWM) strategies for multilevel Neutral Point Clamped (NPC) are presented. Double star Induction motor is characterized by highly non-linear, complex and time-varying dynamics and inaccessibility of some of the states and outputs for measurements. Hence it can be considered as a challenging engineering problem in the industrial sector. Various advanced control techniques has been devised by various researchers across the world. Some of them are based on the neuro-fuzzy techniques (ANFIS). The main advantage of designing the ANFIS coordination scheme is to control the speed of the DSIM to increase the dynamic performance, to provide good stabilization. To show the effectiveness of our scheme, the proposed method was simul...

The aim of this paper is the determination of a control model of involute gears with respect to θ... more The aim of this paper is the determination of a control model of involute gears with respect to θm, based on the application of neural networks. Neural networks are appropriate for the diagnosis of complex systems and control because of its ability to handle data input and output without the need for analytical details of the system. First, we must know the angle to wipe the edge of a tooth surface, with. We acquire the points entered in standard path of the tooth. Then we execute the neurons on these points to determine the weights is the step that is called learning networks. That last request 94.41s. So it becomes all models of the gear standard with the same characteristics. So, if we wanted a control gear of the same module, it will be only a few points seized by CMMs. On the other hand, is looking for the model of the wheel to control the proper starting weight calculated from previous models. His duration of control esteem 1.6 s. Moreover, we can evaluate the deformities of g...

In this work, an experimental study was conducted with the objective of achieving a microscopic c... more In this work, an experimental study was conducted with the objective of achieving a microscopic characterization of samples aged of wastewater and sewer pipes HDPE reinforced with glass fibers in a H2SO4 solution with different concentrations, using the Microscope scanning electron (SEM). The microscopic results show that degradation at the fiber / matrix interface worsens as the increase of the concentration of H2SO4.

Identification of nonlinear metal cutting dynamics with respect to machine tool response is impor... more Identification of nonlinear metal cutting dynamics with respect to machine tool response is important for predicting the occurrence of chatter vibration onset (limit of stability). The present paper deals with constitutive modelling of nonlinear metal cutting dynamics with respect to machine tool response. An adopted approach to predict the occurrence of threshold of chatter vibration from the view point of energy transfer in regenerative chatter is to use an analytical formulation which is concerned with the analysis of chatter vibration. Results of this investigation reveal, that machining process develop some energy which is absorbed by the considering structure. The limit of chatter vibration is achieved only when the energy received by the vibrating process is exactly equal to the energy dissipated by the structural damping. The relationship between the oscillating cutting forces and tool vibration is developed. The present analysis reveals that this relationship exhibits an ac...

SPIN, 2020

Full-Heuslers are a group of materials that have repeatedly attracted the curiosity of scientists... more Full-Heuslers are a group of materials that have repeatedly attracted the curiosity of scientists and researchers, especially for their use in the field of spintronics. In this work, we undertook a study on the structural, elastic, electronic, magnetic and thermodynamic properties of the full-Heusler Mn2OsGe alloy using the calculations of the first principles. Two approximations are used: the generalized approximation of the Perdew–Burke–Ernzerhof GGA–PBE gradient for electron-correlation exchange and the new modified Tran-Blaha form of the modified Becke-Johnson mBJ–GGA-PBE potential. As important results, we found that the compound Mn2OsGe is stable in the CuHg2Ti structure; on the other hand, we could also verify its mechanical stability at zero temperature and pressure. For the calculation of the electronic properties, we were able to determine the half-metallic ferrimagnetic character of our compound, which exhibits a metallic behavior in the state of the majority spins, and a...

MOJ Applied Bionics and Biomechanics, 2017

The results of a quasi-static analysis of the finite elements and the modeling of the mechanical ... more The results of a quasi-static analysis of the finite elements and the modeling of the mechanical (thermo-viscoplastic) behavior of the material are presented using the constitutive law of Johnson-Cook. This law of behavior being pre-integrated into the ABAQUS code. We were particularly interested in the influence of the mechanical behavior and the nature of the target material on its response to the impacter which is supposed to be rigid.