基于主S-N曲线法的焊接结构虚拟疲劳试验理论与应用

The theory and application of the virtual fatigue test of welded structures based on the master S-N curve method

关键词:  焊接结构  疲劳损伤  虚拟疲劳试验  主S-N曲线法  应力集中

Key words:  welded structure  fatigue damage  virtual fatigue test  the master S-N curve  stress concentration

摘要:

讨论了焊接结构虚拟疲劳试验技术的必要性与可行性.围绕美国机械工程师协会ASME(2007)标准中公开发表的用于焊接结构疲劳寿命评估的一个新方法:主S-N曲线法,进行了理论探讨,并认为它是基于焊接结构疲劳破坏机理的,因而比基于名义应力的方法更适合被选择为焊接结构虚拟疲劳试验的核心算法.介绍了两个典型的工程应用案例.结果表明,在设计阶段,基于主S-N曲线的焊接结构虚拟疲劳试验技术,可以有效地识别复杂焊接结构上每一条焊缝上的应力集中,这对设计修改具有很好的指导意义.

Abstract:

The necessity and feasibility of the virtual fatigue test technology of welded structure were discussed firstly. Then a basic theory of a new method called the master S-N curve method,which can be used for assessment of fatigue life of welded structure and published by the ASME (2007) standard, has been discussed as well. Following this discussion,a conclusion has been given that is the new method is resulted from the welded structure fatigue failure mechanism instead of fatigue failure test data. So this method is more suitable as the core algorithm in welding virtual fatigue test then nominal stress method. Finally,two applications have been given,and the results show that during the design phase,the welded structure virtual fatigue test technology based on the master S-N curve method,can effectively identify stress concentrations happed at each weld in a complex welding structure. In fact,this just is needed in design process.