基于权函数法的含裂纹叶片的应力强度因子研究

Research on Stress Intensity Factors of Cracked Blades Based on the Weight Function Method

基于两个已知的参考应力强度因子和权函数的基本特性,分别计算了含单边裂纹、双边裂纹和中心裂纹的有限宽板的权函数。然后,将所计算的权函数分别用于确定含单边、双边及中心裂纹的旋转平板叶片的裂尖应力强度因子K。最后,在线弹性断裂力学范围内由断裂准则K<KIC分别对含单边、双边和中心裂纹的平板叶片的临界转速进行了估算。研究结果表明:旋转平板叶片所含的裂纹深度越深、裂纹位置距旋转轴越近,所引起的裂尖应力强度因子就越大,所允许的临界转速就越低。

The weight functions for the finite width plates with the single edge crack, double edge crack and center crack are, respectively, calculated based on two known reference stress intensity factors and the characteris- tic properties of the weight function. Then, the obtained weight functions are, separately, used to determine the stress intensity factors K near the crack tip of the single edge crack, double edge crack and center crack in the rota- ting plate blades. Finally, the critical rotating speeds of the plate blades with the single edge crack, double edge crack and center crack are, respectively, computed by use of the fracture law （K 〈KIC） in the range of linear elas- tic fracture mechanics. It is found that the increasing crack depth and the reducing distance from the crack line to the rotating axis will lead to a higher stress intensity factor near the crack tip, and a lower allowed critical rotating speed of the plate blade.