Abstract

Within the framework of the processes of formatted, in metal powder close die compaction-sintering makes it possible to combine strong rate of production, minimum of raw material loss and minimum of resumption of machining. The object of this thesis is modelling and the numerical simulation of this process. This work made it possible to highlight the deficiencies of the current modelling of the behaviour of the metal powders. In order to stage this failure, it is proposed an isotropic transverse non-linear elastic model. This model is extensible with varied non-linearity and a more general anisotropy. Moreover, this model takes into account the evolution of the anisotropy that was observed during the densification of a cylinder formatted by close die compaction. For the plastic part of the behaviour, theories on the transformation of the stress' space are exposed in order to take into account the anisotropy recently highlighted. For the hour, plasticity is modelled by isotropic laws of behaviour. Furthermore, some results of numerical simulations on industrial cases are exposed and are compared with experimental measurements. Several finite elements' models were tested. It results from it from good approximations on the level of the distributions of densities (3%). The taking into account of the whole of the phases of compaction-discharge-ejection seems to improve the precision of these distributions. The efforts still suffer from a strong inaccuracy (30%). This seems attributable to the not-catch in account of elastic behaviour during the experimental data processing. Lastly, a parametric study was carried out on the coefficients of the law of behaviour. It results from it that the distributions of densities are less sensitive than the compressive forces to these variations. Moreover, the parameters that have the most influences relates to the mechanism of densification that is requested the most.