车辆点焊结构的非线性力学特性

Nonlinear mechanical properties of spot-welded structures for automobile

在点焊接头组织、结构特性分析的基础上,采用局部应力分析方法,研究了点焊搭接结构在拉伸剪切状态下焊点处的非线性力学特性,建立了弹塑性条件下的非线性有限元模型.研究结果表明:应力在焊点上的分布是不均匀的,且存在较明显的应力集中现象.应力集中主要出现在焊点与板的结合面处.与正应力相比,剪应力在边缘部位的应力集中现象更为明显,因此,剪应力应作为车辆点焊结构安全评价的主要判据.

Based on the analysis of the texture and structure properties of spot-welded joints, the local stress analysis method was applied to study the nonlinear mechanical properties of the welded spots in a tensile-shear spot-welding lap structure. The nonlinear finite element model was established under the condition of elastic-plasticity. The results show that the stress distribution on the welded spot is non-uniform. There is a major stress concentration which occurs in the interface between the welded spot and beard. The shear stresses are more significant compared with the normal stresses near the margin. The shear stresses should be the main criterion for the safety evaluation on the spot-welded structures for automobile.