A two-scale generalized finite element method for parallel simulations of spot welds in large structures

Abstract

The diameter of spot welds used in the automotive and aerospace industry is orders of magnitude smaller than the dimensions of the structural components. Automotive bodies typically have between three and five thousand spot welds which makes 3-D Direct Finite Element Analysis (DFEA) of this class problem not practical. To circumvent these limitations of the FEM, spot welds are idealized in industrial problems as elastic or rigid beams connecting nodes of the metal sheet meshes. However, parameters used in these spot weld models are often problem dependent. This paper presents a parallel Generalized Finite Element Method (GFEM) for the simulation of spot welds in large structures. The proposed GFEM can adopt structural-scale meshes that ignore the spot welds and thus can be generated much quicker than in a DFEA. The element size in the GFEM mesh is of the same order as those used in the industry for the class of problems considered here. Verification problems show that the proposed method can provide an accuracy comparable to a 3-D DFEA. Numerical experiments on a hat-stiffened panel with 168 spot welds show that the proposed GFEM scales much better than a DFEA on shared memory machines, in particular when nonlinear material behavior near the spot welds is considered.