随机应力过程下半椭圆型表面裂纹的扩展

本文应用随机平均原理研究了在随机载荷作用下具有随机抗裂特性的构件所含半椭圆型表面裂纹的疲劳扩展。导出了支配半椭圆型表面裂纹尺寸的转移概率密度的ＦＰＫ方程，给出了裂纹扩展方程在表面和深度两个方向互不耦合情形下的解析解。通过数例详细考察了具有确定性抗裂特性的构件所含半椭圆型表面疲劳裂纹在平稳窄带高斯应力作用下的扩展行为，并有和数字模拟验证方法的有效性。

SEMI-ELLIPTICAL SURFACE CRACK GROWTH UNDER RANDOM LOADING

The semi-elliptical surface crack growth of structural components with uncertain material resistance under random loading is studied by using the stochastic averaging principle. The FPK equation governing the transition probabilisity density function of crack lengths is derived. The analytical solution of the FPK equation for the case that the equations for the crack growth in the surface and depth directions are uncoupled is obtained. The effect of the parameters of the stress process and the material property on the behavior of semi-elliptical fatigue crack growth of the components with deterministic resistance to crack growth under narrow-band stationary Gaussian stress process are examined. The comparison of the analytical result with digital simulation shows the effectiveness of the present method.