点焊过程力学特征的有限元分析

电阻点焊过程中的力学特征对焊点性能和焊接结构的质量有重要影响。文中基于ANSYS有限元系统，建立二维轴对称热弹塑性有限元模型，对点焊过程中的力学特征进行分析。分析中将预先得到的点焊瞬态温度场作为节点温度载荷施加于模型上，同时考虑随温度变化的材料性能及其塑性行为。通过分析得到结合面和电极一工件界面上的接触压力、点焊接头中的应力、应变、变形以及电极位移等力学特征的分布及变化情况。同时参考分析结果进行粘接点焊的试验研究，表明粘接点焊可以显著提高结构的强度和疲劳寿命。

FINITE ELEMENT ANALYSIS FOR THE MECHANICAL FEATURES OF RESISTANCE SPOT WELDING PROCESS

A 2D axisymmetric model of thermo-elastic-plastic finite element method(FEM) was developed to analyze the mechanical behavior of resistance spot welding(RSW) process using commercial software ANSYS.A transient temperature field obtained from a prior performed thermal-electrical simulation of RSW was applied as nodal load on the model.The temperature dependent material properties and plastic behavior of the workpiece and the electrode were accounted for during the simulation.The distributions and change histories of the contact pressure at both the faying surface and the electrode-workpiece interface are obtained through the analysis.The stress and strain distributions in the weldment and their changes during the RSW process are determined.The deformation of the weldment and the electrode displacement due to the thermal expansion and contraction are also calculated.Weldbonding experiments were performed and the results show that weldbonding technique can improve the strength and fatigue life of the weld joint.