冷挤压孔边残余应力场中裂纹的应力强度因子

 本文给出了复杂应力场中圆孔边穿透裂纹问题的权函数解析解和各种基本载荷作用下孔边裂纹的应力强度因子计算公式。并据此计算了冷挤压孔边残余应力场中裂纹的应力强度因子,进而讨论了裂纹在外载荷和残余应力共同作用下疲劳扩展的特点。

RESIDUAL STRESS INTENSITY FACTORS FOR RADIAL CRACKS AT THE EDGE OF A COLD-WORKED HOLE

Coldworking of fastener holes has been utilized as an effective technique in aerospace industry to enhance structural components' fatigue and fracture performance. To quantify the benifical effects of coldworking, stress intensity factors for radial cracks in residual stress fields around the cold-worked hole must be known. Due to the complexity of residual stress distributions, the existing stress intensity factor solution methods are difficult to be used for such problems because they will be loo complicated and time-consuming.in this paper an analytical method for the computation of stress intensity factors for a throuh-the-thickness radial crack at the edge of a circular hole has been presented. The method is based on tite weight function theory in fracture mechanics. The approach is versatile, cost-effective and simple-to-use. and the solution accuracy is very good. Stress intensity factors formulae for such cracks subjucted to various basic load distributions were derived. A technique enabling stress intensity factors to be determined with point-by-point loading specification for a number of points on the crack face was presented. The developed analytical expressions allow stress intensity factors for complex load situations to be determined with minimum efforts.The paper further made a detailed analysis for crack problems involving residual stress fields around a cold-worked hole. Fatigue crack propagation characteristics lor such cracks subjucted o combined action of external loading and residual stress were discussed. The results of this study can be used in quantitative damage-tolerance analysis for aerospace structures containing cold-worked or interference-fitted holes subjected to arbitrary external loading.