Abstract

Welded structures are commonly used in the industry, especially, in the transport sector. Indeed, when these structures are subjected to the cyclic loadings, the analysis of the fatigue strength of welded joints became very important and quite complicated. There are many factors underlying this problem. The most critical of these factors that affect the resistance of fatigue is the nature of the material chosen, the detail of geometry, and the residual stress, as well as the yield stress of the base metal. It is for this reason that many authors and engineers have recommended some historic methods and standards to predict the life time of structures. The most used methods are the chapter 9 of Eurocode 3, the local deformation method and the British Standard, but these methods lack precision. Recently new approaches have emerged the hot spot and the volumetric method to determine the effective stress in the plastic zone near the weld. The comparisons between these new approaches have concluded that the volumetric method encompasses a number of advantages over the standards applied. In the future work, the author will apply the volumetric method on a model based on a welded structure used in the automotive domain in order to predict the fatigue life, then, the results obtained from this method will be validated using the experimental test and the numerical simulation results.

摘要

焊接结构在工业中普遍使用，尤其是在运输领域。事实上，当这些结构承受循环载荷时，焊接接头的疲劳强度分析变得非常重要且相当复杂。这个问题背后有很多因素。这些影响抗疲劳性的因素中最关键的是所选材料的性质、几何形状的细节、残余应力以及母材的屈服应力。正是出于这个原因，许多作者和工程师推荐了一些历史性的方法和标准来预测结构的寿命。最常用的方法是欧洲规范 3 的第 9 章、局部变形法和英国标准，但这些方法缺乏精确性。最近出现了新的方法，即热点法和体积法来确定焊缝附近塑性区的有效应力。这些新方法之间的比较得出的结论是，体积方法比所应用的标准具有许多优势。在未来的工作中，作者将在汽车领域使用的基于焊接结构的模型上应用体积法来预测疲劳寿命，然后通过实验测试验证该方法获得的结果和数值模拟结果。