The coupled thermomechanical computational modeling of metal casting processes has been one of the research topics of great interest over the last years. However, despite the considerable advances achieved in computational mechanics, the large-scale numerical simulation of these processes continues to be nowadays a very complex task. This is mainly due to the highly nonlinear nature of the problem, involving nonlinear material models, liquid-solid phase change, nonlinear thermomechanical boundary conditions and thermomechanical contact, among others. In this paper, current developments to deal with an accurate, efficient and robust coupled thermomechanical computational simulation of metal casting processes is presented. A thermodynamically consistent constitutive material model is derived from a thermoviscoplastic free energy function. A continuous transition between the initial fluid-like and the final solid-like is modeled by considering a J2 thermoviscoplastic model. Thus, an thermoelastoviscoplastic model, suitable for the solid-like phase, degenerates into a pure thermoviscous model, suitable for the liquid-like phase, according to the evolution of the solid fraction function [1-2]. A thermomechanical contact model, taking into account the insulated effects of the air-gap due to thermal shrinkage of the part during solidification and cooling, is introduced [1-2]. A fractional step method, arising from an operator split of the governing differential equations, is considered to solve the coupled problem using a staggered scheme [1-2]. Within a finite element setting, using low-order interpolation elements, a multiscale stabilization technique is introduced as a convenient framework to overcome the Babuska-Brezzi condition and avoid volumetric locking and pressure instabilities arising in incompressible or quasi-incompressible problems [3-4]. Computational simulation of industrial castings show the good performance of the model.
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