Fatigue degradation strategies to simulate crack propagation using peridynamic based computational methods

Abstract The aim of this paper is to develop new computational tools to study fatigue crack propagation in structural materials. In particular we compare the performance of different degradation strategies to study fatigue crack propagation phenomena adopting peridynamic based computational methods. Three fatigue degradation laws are proposed. Two of them are original. Initially a cylinder model is used to compare the computational performance of the three fatigue laws and to study their robustness with respect to variations of discretization parameters. Then the fatigue degradation strategies are implemented in a peridynamic framework for fatigue crack propagation analyses. Both cylinder model and peridynamic simulations show that the third proposed degradation law is unique in its combination of high accuracy, high stability and low computational cost.

摘要 本文旨在开发新型计算工具，用于研究结构材料的疲劳裂纹扩展问题。具体而言，本文采用基于近场动力学（peridynamic）的计算方法，对比不同退化策略在研究疲劳裂纹扩展现象时的性能表现。本文共提出三种疲劳退化准则，其中两项为原创性准则。首先，借助圆柱模型对比三种疲劳退化准则的计算性能，并考察其对离散化参数变化的鲁棒性；随后，将所提出的疲劳退化策略集成至近场动力学框架中，用于开展疲劳裂纹扩展分析。圆柱模型与近场动力学模拟结果均证实，所提出的第三种退化准则兼具高精度、高稳定性与低计算成本，这一综合特性实属独有。