A multi-scale finite element modeling approach was developed to study the deformation and fracture behavior of Al-steel resistance spot welds. First, a micro-scale model was applied to simulate the mechanical responses of the intermetallic compound (IMC) layer having various morphologies and thicknesses under tensile and shear loading conditions. Second, the predicted tensile and shear strength of the IMC layer, that varied along the joint interface per the IMC layer morphology and thickness variation, was then introduced into 3D macro-scale models to predict the overall mechanical performance of weld coupons under coach peel, lap shear and cross-tension testing conditions. The numerical predictions agreed reasonably well with the experimental data.

研究了一种多尺度有限元建模方法，以研究铝钢电阻点焊的变形和断裂行为。首先，应用微型模型来模拟在拉伸和剪切载荷条件下具有各种形态和厚度的金属间化合物（IMC）层的机械响应。其次，将预测的IMC层的拉伸强度和剪切强度（沿每个IMC层的形态和厚度变化沿接合面变化）引入到3D宏观模型中，以预测在教练剥离下焊片的整体机械性能，搭接剪切和横向张力测试条件。数值预测与实验数据吻合得很好。