The goal of this work, which has been done within the framework of a European project, was the numerical simulation of the injection of a semi-solid aluminium alloy. In order to reach this objective, the work has been divided into two major parts, which are the experiments and the numerical simulation. Concerning the experiments, the goal was to found a constitutive law and its parameters that characterised as well as possible the behaviour of our alloy in the semisolid state. Therefore we made first a bibliographical study on the laws available from the literature, and we decided to use a viscoplastic law, and then we performed the experiment of the Stephan flow. The experimental results were satisfactory and the identification of parameters had been done, using a trial-error strategy. On the numerical simulation part of the work, we adapted first R3 software to the numerical simulation of semisolid flows, by introducing a modulus contact for the treatment of the folding defects, and we also worked on the contact between rigid moulds and the fluid. We then had a problem of conditioning number for the hessian matrix. This problem had been solved by the use of the uncompleted factorisation of Crout as preconditioner. We then work on the arbitrary lagrangian eulerian formulation and on the automatic mesh generation. Unfortunately, we didn't succeed in the total simulation of the filling of industrial moulds. So, we decided to use Rem3D software, initially developed for the injection of thermoplastics, using a eulerian formulation. We introduced the inertial effects and the constitutive law in Rem3D software, and we simulated the injection of our semisolid aluminium alloys in industrial moulds. The results showed a good agreement between experimental results and numerical simulations. So this software can now constitute a good implement for the conception assistance.
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