金属基陶瓷涂层/钢基体界面裂纹的应力强度因子

Stress intensity factor of interfacial crack between metal-base ceramic coating and steel

摘要: 将三点弯曲断裂力学试验与有限元分析(FEA)结合起来计算LX88A涂层与Q345钢界面裂纹的复应力强度因子。结果表明,对于三点弯曲试样,当发生界面断裂的临界载荷较小时,涂层试样的界面裂纹尖端附近存在K控制区,但K因子随临界载荷的增大,K因子控制区消失,发生K失效的现象。对于三点弯曲试样,当临界载荷超过一定值时,线弹性断裂力学已经不能描述界面裂纹尖端场。因此,在后续研究中有必要使用弹塑性断裂力学和概率断裂力学对此类界面裂纹进行分析。

Abstract: The three-point bending fracture mechanics experiments and finite element analysis had been used to compute the complex stress intensity factor (K)of the interfacial crack between LX88A coating and Q345 steel.It was found that the K-dominant zone exist near the crack tip only for some specimens.The result indicates that K_C can not be used as the single fracture parameter to evaluate the interface fracture behavior for three-point bending specimen. Therefore, it is necessary that the elastic-plastic fracture mechanics and probabilistic fracture mechanics are used to analyze such interface cracks.