多点裂纹起始过程的计算机模拟

Computer Simulation on Process of Multi-Crack Initiation

在多点裂纹起始的情况下,可以观察到多个微观裂纹的萌生和早期扩展,所以宏观裂纹形成的寿命估算是比较复杂的。本文介绍一种二维计算机模型,模拟一种马氏体钢F82H的多点裂纹起始过程,损伤的累积程度通过单位面积裂纹密度表示,微裂纹萌生循环数通过Tanaka-Mura公式确定。该模型可以模拟材料的微观结构参数(如晶粒尺寸和取向)对裂纹萌生寿命的影响,给出定量的寿命估算表达式。模拟的裂纹密度和循环数的关系与试验结果符合得相当好。

A two-dimensional computer simulation on the process of multi-crack initiation was described. The damage accumulation was presented by the crack density per unit area. The number of cycles to crack nucleation was estimated by the Tanaka-Mura equation. The model simulated the microstructural parameters influences （such as grain size and orientation） on fatigue life. A quantitative prediction was obtained. The model was applied to simulate the multi-crack initiation in a martensitic steel F82H. The results from simulation coincided with experimental data quite well.