基于连续损伤力学的高低周复合疲劳损伤

基于连续损伤力学(CDM)的经典损伤理论和不可逆热力学原理,分别对高周和低周疲劳载荷下的损伤演化模型进行了研究,进而推导出一个新的高低周复合疲劳损伤模型;将该模型编写为UMAT耦合到ABAQUS有限元分析软件中,实现了对缺口材料高低周复合疲劳损伤的模拟及裂纹萌生位置和萌生寿命的预测;同时研究了不同的高低周循环比对裂纹萌生寿命的影响.结果表明,裂纹容易在缺口根部应力集中处萌生;该模型考虑了高低周循环的交互作用,模拟计算结果更符合实际情况;同时通过研究发现高的循环比会使裂纹的萌生加速.

High cycle and low cycle hybrid fatigue damage based on continuum damage mechanics

Based on the continuum damage mechanics (CMD) and irreversible thermodynamics framework, a damage evolution model was investigated under high cycle and low cycle fatigue, respectively, and a new damage model was developed for high cycle and low cycle hybrid fatigue. A user defined material subroutine (UMAT) was compiled and coupled to ABAQUS finite element analysis software. The simulation of high-low cycle fatigue damage and the prediction of crack initiation position and life of notched materials were carried out. Simultaneously, the influence of different high cycle and low cycle ratios on the crack initiation life was studied. The results reveal that the crack was easy to initiate at the stress concentration spot of the notched root. As the interaction of high cycle and low cycle damage was taken into account, the simulated results were more in accord with the practical situation. Meanwhile, the high cycle ratio would accelerate the crack initiation.