涂层中裂纹应力强度因子的计算及裂纹扩展

Calculation of Crack Stress Intensity Factors and Crack Propagation in Coating

在涂层工作过程中,由于喷涂材料硬度高、抗裂性能差、喷涂工件刚性大工件表面产生应力集中,涂层很容易产生裂纹.对于含初始裂纹的喷涂材料,在拉伸载荷作用下裂纹的扩展与裂尖应力强度因子有很大的关系,根据断裂力学的基本原理,提出了利用数值模拟的方法来计算裂纹尖端的应力强度因子.并讨论了裂纹前沿网格划分对应力强度因子的影响,预测了裂纹扩展时形状的变化.

Because of the high hardness and low crack-resistance of spray material, and the high rigidity of spray workpieees, and the stress convergence on the coating surface, cracks tend to result on the coating. To the initial spray material with a crack, the propagation path of the crack in the material under tensile load has much to do with the stress intensity factor. According to the basic principle of the fracture mechanics, this paper proposes the numerical method to calculate the stress intensity factor of the crack tip, discusses the effect of crack front grid partition on stress intensity, and predicts the shape changes during the propagation of crack.