用光弹性方法研究厚壁压力容器内表面裂纹的应力强度因子

Determination of Stress Intensity Factor at Inner Surface Crack in Thick Wall Pressure Vessel by Photoelastic Method

本文针对三维裂纹纹尖的应力状态及裂纹表面均匀受压的情况,用应力函数法导出了纹尖附近区域应力级数解;用光弹性方法测定厚壁压力容器内表面沿90°(纵方向),57°,41°,27°,0°(横方向)布置的圆形裂纹应力强度因子K_Ⅰ,K_Ⅱ和K_Ⅲ的分布;在光弹分析中引入了二阶非奇异项,并在数据处理中采用了阻尼最小二乘法以获得精度较高的解。

In this paper, according to the uniform pressure on crack surface and three dimensional (3-D) state of stress field around crack tip, the stress was derived in series form by means of stress function. The stress intensity factors (S. I. F. ) K_Ⅰ, , K_Ⅱ, and K_Ⅲ, of coin—shaped inner crack located along the directions of 90°(longitudinal), 57°, 41°, 27°and 0°(horizontal) in the thick wall pressure vessel were determined by 3D photoelastic method. Higher accurate result was obtained by introducing second order terms of nonsingularity into experimental stress analysis and using the damping least square method in data processing.