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 10 10 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.

Application of Subloading Surface Model to Heat Treatment Simulation Based on Explicit Finite Element Method

“…Since it is necessary to solve the simultaneous equation in order to calculate the displacement increment implicitly, the heat treatment simulation of the large scale model could require the impractical computational time. In order to solve this problem, the explicit analysis and the mass scaling method could be applied for the heat treatment simulation [1]. The explicit analysis does not need to solve the simultaneous equation and can reduce the computational time more than that of the implicit analysis.…”

“…In the explicit analysis, the mass scaling method was applied with the mass scaling factors 10 9 , 10 10 , 10 11 and 10 12 . Since the inertia of the heat treatment is small, the extremely large mass scaling factor can be used [1].…”