https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Sun, 10 May 2026 07:54:34 GMT 2026-05-10T07:54:34Z http://hdl.handle.net/10985/9960 Numerical and Experimental Approach in Assisted Cryogenic Machining TRABELSI, Sabrine; BOUAZIZ, Zoubeir; MOREL, Anne; GERMAIN, Guénaël Understanding of local mechanisms chip forming during machining by removal of material is difficult, to this end; a cutting finite element modelling is required. This study aims initially to model orthogonal cutting of Ti17 titanium alloy in dry and cryogenic machining and in a second time to study the influence of the application of cryogen during machining on temperature fields and cutting forces in numerical simulation. An experimental study was also conducted to determine the mode of tool wear and the evolution of flank wear. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9960 2015-01-01T00:00:00Z TRABELSI, Sabrine BOUAZIZ, Zoubeir MOREL, Anne GERMAIN, Guénaël Understanding of local mechanisms chip forming during machining by removal of material is difficult, to this end; a cutting finite element modelling is required. This study aims initially to model orthogonal cutting of Ti17 titanium alloy in dry and cryogenic machining and in a second time to study the influence of the application of cryogen during machining on temperature fields and cutting forces in numerical simulation. An experimental study was also conducted to determine the mode of tool wear and the evolution of flank wear. http://hdl.handle.net/10985/11145 Numerical analysis of constitutive coefficients effects on FE simulation of the 2D orthogonal cutting process: application to the Ti6Al4V YAICH, Mariem; AYED, Yessine; BOUAZIZ, Zoubeir; GERMAIN, Guénaël In this paper, a deep study of constitutive parameters definition effect is done in order to guarantee sufficient reliability of the finite element machining modeling. The case of a particular biphasic titanium alloy Ti6Al4V known by its low machinability is investigated. The Johnson-Cook (JC) elasto-thermo-visco-plastic-damage model combined with the energy-based ductile fracture criteria is used. Segmentation frequency, chip curvature radius, shear band spacing, chip serration sensitivity and intensity, accumulated plastic strain in the formed chip segments, and cutting forces levels are determined where their dependency to every constitutive coefficient is examined and highlighted. It is demonstrated from the separate variation of every plastic and damage parameters that an interesting finite element modeling (FEM) relevance is reached with the adjustment of JC strain hardening coefficients term, thermal softening parameter, exponent fracture factor, and damage evolution energy. Moderate and high cutting speeds are applied to the cutting tool in the aim to test their impact on shear localization, chip segmentation, and numerical forces levels as well as to approve previous highlighted findings related to constitutive parameters definition. In general, this study focuses on a prominent decrease in identification process cost with the previous knowledge of the most affecting constitutive coefficients while keeping an interesting agreement between numerical and experimental results. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/11145 2016-01-01T00:00:00Z YAICH, Mariem AYED, Yessine BOUAZIZ, Zoubeir GERMAIN, Guénaël In this paper, a deep study of constitutive parameters definition effect is done in order to guarantee sufficient reliability of the finite element machining modeling. The case of a particular biphasic titanium alloy Ti6Al4V known by its low machinability is investigated. The Johnson-Cook (JC) elasto-thermo-visco-plastic-damage model combined with the energy-based ductile fracture criteria is used. Segmentation frequency, chip curvature radius, shear band spacing, chip serration sensitivity and intensity, accumulated plastic strain in the formed chip segments, and cutting forces levels are determined where their dependency to every constitutive coefficient is examined and highlighted. It is demonstrated from the separate variation of every plastic and damage parameters that an interesting finite element modeling (FEM) relevance is reached with the adjustment of JC strain hardening coefficients term, thermal softening parameter, exponent fracture factor, and damage evolution energy. Moderate and high cutting speeds are applied to the cutting tool in the aim to test their impact on shear localization, chip segmentation, and numerical forces levels as well as to approve previous highlighted findings related to constitutive parameters definition. In general, this study focuses on a prominent decrease in identification process cost with the previous knowledge of the most affecting constitutive coefficients while keeping an interesting agreement between numerical and experimental results. http://hdl.handle.net/10985/16584 Tool wear and cutting forces under cryogenic machining of titanium alloy (Ti17) TRABELSI, Sabrine; MOREL, Anne; GERMAIN, Guénaël; BOUAZIZ, Zoubeir Titanium alloy is well known for its difficulty to machine, owing to the important “tool wear” phenomenon. Machining assistance is an interesting solution to lengthen the tool lifetime. In this study, we focused on the effect of cryogenic assistance—during machining of Ti17—on the tool wear and cutting forces for different combinations of cutting speed, feed rate and depth of cut. Compared to conventional lubrication, cryogenic support lengthens the tool life for all tested conditions and has no significant influence on cutting force. A comparison of the cryogenic effect and high-pressure water jet assistance is also presented. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/16584 2016-01-01T00:00:00Z TRABELSI, Sabrine MOREL, Anne GERMAIN, Guénaël BOUAZIZ, Zoubeir Titanium alloy is well known for its difficulty to machine, owing to the important “tool wear” phenomenon. Machining assistance is an interesting solution to lengthen the tool lifetime. In this study, we focused on the effect of cryogenic assistance—during machining of Ti17—on the tool wear and cutting forces for different combinations of cutting speed, feed rate and depth of cut. Compared to conventional lubrication, cryogenic support lengthens the tool life for all tested conditions and has no significant influence on cutting force. A comparison of the cryogenic effect and high-pressure water jet assistance is also presented. http://hdl.handle.net/10985/21315 Numerical analysis of the Ti6Al4V behavior based on the definition of a new phenomenological model YAICH, Mariem; AYED, Yessine; GERMAIN, Guénaël; BOUAZIZ, Zoubeir The finite element modeling is significantly dependent on the accurate prediction of the material behavior. In order to increase the accuracy of numerical simulations, a new phenomenological model is proposed in this study. Its mathematical formulation allows suitable predictions of the Ti6Al4V sensitivity to strain rates and temperatures, while maintaining a low identification cost of its constitutive coefficients.A subroutineVUMATis developed, and its reliability is investigated in the case of themodeling of uniaxial tensile and impact tests. In addition, the 3D numerical analysis of the machining process is investigated based on the definition of the rheological Johnson-Cook model and the proposed one. Experimental orthogonal machining tests are also established for several cutting conditions. The significant sensitivity of the chip serration, the segments geometry, and the cutting forces to the feed rate is pointed out. Comparisons of the numerical results corresponding to different constitutive models are carried out. High-correlation levels with the experimental results are reached with the definition of the proposed phenomenological model, which is not the case of the Johnson-Cook empirical law.Moreover, intuitive insights about the effect of cutting conditions on the material flow towards the workpiece edges are provided with the 3D modeling. A pronounced increase of the width of side burrs with the feed rate rise was underlined. The results presented in this study point out the inability of 2D numerical simulations to accurately predict the phenomena induced during the machining process, even in the case of an orthogonal machining Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/21315 2021-01-01T00:00:00Z YAICH, Mariem AYED, Yessine GERMAIN, Guénaël BOUAZIZ, Zoubeir The finite element modeling is significantly dependent on the accurate prediction of the material behavior. In order to increase the accuracy of numerical simulations, a new phenomenological model is proposed in this study. Its mathematical formulation allows suitable predictions of the Ti6Al4V sensitivity to strain rates and temperatures, while maintaining a low identification cost of its constitutive coefficients.A subroutineVUMATis developed, and its reliability is investigated in the case of themodeling of uniaxial tensile and impact tests. In addition, the 3D numerical analysis of the machining process is investigated based on the definition of the rheological Johnson-Cook model and the proposed one. Experimental orthogonal machining tests are also established for several cutting conditions. The significant sensitivity of the chip serration, the segments geometry, and the cutting forces to the feed rate is pointed out. Comparisons of the numerical results corresponding to different constitutive models are carried out. High-correlation levels with the experimental results are reached with the definition of the proposed phenomenological model, which is not the case of the Johnson-Cook empirical law.Moreover, intuitive insights about the effect of cutting conditions on the material flow towards the workpiece edges are provided with the 3D modeling. A pronounced increase of the width of side burrs with the feed rate rise was underlined. The results presented in this study point out the inability of 2D numerical simulations to accurately predict the phenomena induced during the machining process, even in the case of an orthogonal machining http://hdl.handle.net/10985/19397 A 2D finite element analysis of the effect of numerical parameters on the reliability of Ti6Al4V machining modeling YAICH, Mariem; AYED, Yessine; BOUAZIZ, Zoubeir; GERMAIN, Guénaël The numerical analysis, based on the finite element modeling (FEM), presents nowadays an efficient computational tool. It allows a better understanding of several thermo-mechanical phenomena involved during the machining process. However, its reliability heavily depends on the accurate definition of the numerical model. In this regard, a FE analysis focused on the 2D modeling of the Ti6Al4V dry orthogonal machining was carried out in this study. The relevance of different numerical meshing approaches and finite elements topologies was studied. The effect of the friction coefficient on the numerical chip morphology, its geometry, the cutting and the feed forces was investigated. The adequacy of several compared adaptive meshing approaches, in terms of the modeling of severe contact conditions taking place around the cutting-edge radius, was underlined in the current study. However, numerical serrated chips, closer to the experimental ones, were only predicted when the pure Lagrangian formulation was adopted and a proper determination of the failure energy was carried out. The definition of different mesh topologies highlighted the efficiency of the 4-node quadrangular mesh, with a suitable edge length, in increasing the agreement with the experimental data, while reducing the computing times. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/19397 2020-01-01T00:00:00Z YAICH, Mariem AYED, Yessine BOUAZIZ, Zoubeir GERMAIN, Guénaël The numerical analysis, based on the finite element modeling (FEM), presents nowadays an efficient computational tool. It allows a better understanding of several thermo-mechanical phenomena involved during the machining process. However, its reliability heavily depends on the accurate definition of the numerical model. In this regard, a FE analysis focused on the 2D modeling of the Ti6Al4V dry orthogonal machining was carried out in this study. The relevance of different numerical meshing approaches and finite elements topologies was studied. The effect of the friction coefficient on the numerical chip morphology, its geometry, the cutting and the feed forces was investigated. The adequacy of several compared adaptive meshing approaches, in terms of the modeling of severe contact conditions taking place around the cutting-edge radius, was underlined in the current study. However, numerical serrated chips, closer to the experimental ones, were only predicted when the pure Lagrangian formulation was adopted and a proper determination of the failure energy was carried out. The definition of different mesh topologies highlighted the efficiency of the 4-node quadrangular mesh, with a suitable edge length, in increasing the agreement with the experimental data, while reducing the computing times. http://hdl.handle.net/10985/19398 A 3D Numerical Analysis of the Chip Segmentation Mechanism and the Side Burr Formation During the Ti6Al4V Alloy Machining YAICH, Mariem; AYED, Yessine; BOUAZIZ, Zoubeir; GERMAIN, Guénaël A 3D finite element modeling of the orthogonal turning process was curried out in the current study. It aims to carefully investigate the mechanisms controlling the chip segmentation and the crack propagation direction in the case of the Ti6Al4V machining. Coupled temperature-displacement numerical simulations were performed in the software Abaqus®/Explicit, under different cutting conditions. The instantaneous distribution of numerical thermomechanical variables along the width of cut was investigated. High plastic strains, temperatures and damage were predicted in the median plane of the workpiece, mainly in the shear bands around the tool tip vicinity. Whereas, a reduction of their values was noted while moving towards the chip sides and its upper surface. The 3D numerical simulations pointed out that the orthogonal machining resulted in an increase of the chip width, in addition to the material flow along the X and Y directions. The quantitative analysis of the side burr formation highlighted its sensitivity to the cutting conditions. The definition of high feed rates resulted in pronounced material flow in the workpiece edges, thus the modeling of wider chip. The present study concluded that the chip segmentation is a 3D mechanism. In addition, it pointed out the limitations of the 2D numerical simulations, as well as the inadequacy of the plain strain hypothesis, even in the case of the orthogonal machining. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/19398 2020-01-01T00:00:00Z YAICH, Mariem AYED, Yessine BOUAZIZ, Zoubeir GERMAIN, Guénaël A 3D finite element modeling of the orthogonal turning process was curried out in the current study. It aims to carefully investigate the mechanisms controlling the chip segmentation and the crack propagation direction in the case of the Ti6Al4V machining. Coupled temperature-displacement numerical simulations were performed in the software Abaqus®/Explicit, under different cutting conditions. The instantaneous distribution of numerical thermomechanical variables along the width of cut was investigated. High plastic strains, temperatures and damage were predicted in the median plane of the workpiece, mainly in the shear bands around the tool tip vicinity. Whereas, a reduction of their values was noted while moving towards the chip sides and its upper surface. The 3D numerical simulations pointed out that the orthogonal machining resulted in an increase of the chip width, in addition to the material flow along the X and Y directions. The quantitative analysis of the side burr formation highlighted its sensitivity to the cutting conditions. The definition of high feed rates resulted in pronounced material flow in the workpiece edges, thus the modeling of wider chip. The present study concluded that the chip segmentation is a 3D mechanism. In addition, it pointed out the limitations of the 2D numerical simulations, as well as the inadequacy of the plain strain hypothesis, even in the case of the orthogonal machining.