Modélisation numérique de la coupeétude de sensibilité des paramètres d'entrée et identification du frottement entre outil-copeau

Abstract

Numerical cutting modelling, taking into account material's non-linear behaviour and the contact phenomena between tool and chip, shows up as finer modelling of the cutting process than the analytical one. It allows to access to several thermo-mechanical variables, and thus, to better understanding of the cutting process. After the set up of 2 D and 2ư D numerical cutting models developed under the general purpose Finite Element Analysis software Abaqus, this thesis is focused first, in an intensive sensitivity study to numerical and non-numerical parameters. Second, once shown the tool-chip friction coefficient influence in numerical results, a new methodology is proposed to determine and implement a variable friction coefficient depending on the tool-chip contact point. This methodology, which is extracted from experimental tests, takes into account cutting edge effects. It allows to better match numerical results with experimental ones, regarding cutting forces. It shows as well, remarkable differences in temperature, comparing with the numerical model where a constant friction coefficient is used. Nevertheless, this improvement doesn't allow nowadays to clearly distinguish a standard steel from its homologue with improved machinability. It seems that material behaviour and friction laws, involving microstructural aspects, could be used in the future, in the aim to develop more precise numerical models of the cutting process.