A thermomechanical model for the analysis of light alloy solidification ina composite mould

A coupled thermomechanical model to simulate light alloy solidification pro blems in permanent composite moulds is presented. This model is based on a general isotropic thermoelasto-plasticity theory and considers the differen t thermomechanical behaviours of each component of the mould as well as tho se of the solidifying material during its evolution from liquid to solid. T o this end, plastic evolution equations, a phase-change variable and a spec ific free energy function are proposed in order to derive temperature-depen dent material constitutive laws. The corresponding finite element formulation and the staggered scheme used to solve the coupled nonlinear system of equations are also presented. Fina lly, the temperature and displacement predictions of the model are validate d with laboratory measurements obtained during an experimental trial. (C) 1 999 Elsevier Science Ltd. All rights reserved.