Failure simulation in resistance spot-welded lap-joints using cohesive zone modeling

Abstract

This paper concentrates on simulating fracture in thin walled single-lap joints connected by resistance spot-welding (RSW) process which were subjected to tensile loading. For this purpose, three sets of lap-joints with different spot configurations were tested to achieve the joints’ tensile behavior. To simulate the joints tensile behavior, firstly a 2D axisymmetric finite element (FE) model was used to calculate residual stresses induced during the welding process. Then the results were transferred to 3D models as pre-stress. In this step, cohesive zone model (CZM) technique was used to simulate fracture in the models under tensile load. Cohesive zone parameters were extracted using coach-peel and shear lap specimens. The results were employed to simulate deformation and failure in single lap spot weld samples. It has been shown that considering the residual stresses in simulating deformation and fracture load enables quite accurate predictions.

摘要

本文主要研究电阻点焊(RSW)连接薄壁单搭接头在拉伸载荷作用下的断裂过程。对3 组不同 节点结构的搭接头进行试验, 以获得接头的拉伸性能。为了模拟焊接接头的拉伸行为, 首先采用二维 轴对称有限元模型计算焊接过程中产生的残余应力, 然后将结果转化为三维模型作为预应力。在此基 础上, 采用粘聚区模型(CZM)对拉伸载荷作用下模型中的断裂进行数值模拟。采用拉皮法和剪切搭 接法提取粘聚区参数。用于模拟单搭接点焊试样的变形和失效的结果表明, 在模拟变形和断裂载荷时, 考虑残余应力的影响对保证预测结果的准确性是必要的。