车辆装配前铝合金焊缝节点结构疲劳试验研究

Research on Fatigue Test of Aluminum Alloy Joint Structure before Vehicle Assembly

铝合金焊缝节点结构作为车体结构中的重要组成部分,车辆装配前对焊缝节点结构强度进行研究具有重要意义。为了掌握铝合金焊缝节点结构的疲劳强度性能,选取实车中出现疲劳裂纹破坏的典型节点部位制作标准件进行疲劳试验;根据试件与实际车体疲劳破坏位置的应力分布趋势一致的原则,设计了两种典型焊接形式的标准件结构模型,并且确定了疲劳试验的加载方式以及试验工装设计,给出了试验模型的疲劳破坏位置以及通过成组试验获得的典型节点形式的S-N(应力-寿命)曲线。同时利用非线性有限元方法对铝合金焊缝节点结构进行疲劳强度计算,将计算结果与试验结果进行对比分析,验证了所采用有限元计算方法的准确性和普遍适用性。

The aluminum alloy joint is a crucial component of the vehicle body, the study on the welded joint structure strength before vehicle assembly possesses significant importance.In order to acknowledge the fatigue strength performance of the aluminum alloy joint structure,typical joint with the fatigue crack in actual vehicles were selected,with reference to which,standard joints were made to carry out the fatigue test.According to the principle that the test piece is consistent with the stress distribution tendency of the vehicle body fatigue failure position,two typical welding structure models were designed and the fatigue test loading mode as well as test tool design were validated. The fatigue failure position of testing models and S-N curves of typical joint forms through group experiments were obtained. The fatigue strength calculation of aluminum alloy joint structure was carried out using nonlinear finite element method. The calculation results were compared with the experimental results. The accuracy and universality of the finite element calculation method for the fatigue performance of aluminum alloy joint structures were verified.