论文标题
在激光震动诱导的残留应力下疲劳裂纹生长的相位场模型
Phase-field modelling for fatigue crack growth under laser-shock-peening-induced residual stresses
论文作者
论文摘要
对于薄壁成分的疲劳寿命,不仅疲劳裂纹的启动,而且裂纹生长是决定性的。裂缝的相位场方法是模拟任意裂纹现象的强大工具。最近,它已应用于疲劳裂缝。这些模型为疲劳寿命估计而构成了经典裂缝机械方法的替代方法。在本文的第一部分中,对相位疲劳模型的参数进行了校准,并将其预测与铝板材料的疲劳裂纹生长实验的结果进行了比较。在第二部分中,借助激光减震,将压缩残留应力引入组件中。结果表明,这些残留应力通过延迟和加速裂纹会影响裂纹的生长速率。为了在数值上研究这些疲劳机制,提出并通过实验进行了一个简单的策略,将残留应力纳入相位场疲劳模型中。研究表明,该方法可以再现残余应力对裂纹生长速率的影响。
For the fatigue life of thin-walled components, not only fatigue crack initiation, but also crack growth is decisive. The phase-field method for fracture is a powerful tool to simulate arbitrary crack phenomena. Recently, it has been applied to fatigue fracture. Those models pose an alternative to classical fracture-mechanical approaches for fatigue life estimation. In the first part of this paper, the parameters of a phase-field fatigue model are calibrated and its predictions are compared to results of fatigue crack growth experiments of aluminium sheet material. In the second part, compressive residual stresses are introduced into the components with the help of laser shock peening. It is shown that those residual stresses influence the crack growth rate by retarding and accelerating the crack. In order to study these fatigue mechanisms numerically, a simple strategy to incorporate residual stresses in the phase-field fatigue model is presented and tested with experiments. The study shows that the approach can reproduce the effects of the residual stresses on the crack growth rate.