High-efficiency coupled solidification-thermal stress simulation of casting based on explicit finite element method

Abstract

It is important to develop numerical prediction techniques for solidification and thermal deformation of casting, in order to clarify mechanisms of cast defects, deformation behaviors of cast itself or cracks which appear during solidification. However, non-linearity of such thermo-mechanical phenomena is extremely high, and numerical calculations for such problems often require enormous computational cost. Therefore, there is always a need for simulation method that can allow high efficient calculation on such high non-linearity problems. In this study, a coupled solidification-thermal elasto-plastic simulation model based on dynamic explicit finite element method is developed. Moreover, some numerical approaches such as mass scaling method are applied so as to improve computational efficiency. Using this model, simulation on thermal stress of casting during solidification was conducted for a simple 2D model and a relatively large 3D model of steel ingot casting. In both cases, dynamic effect due to inertia was negligible and mass scaling factor was able to be raised to the order of 1010 without computational instability, resulting in drastic reduction of computational time. These numerical results indicate that explicit mass scaling method has significant effect on improving calculation efficiency, and such method can be a powerful tool for thermal stress simulation of casting.

Keywords

• casting
• solidification
• thermal stress
• explicit finite element method
• mass scaling