二维裂纹传播的动光弹性分析

Dynamic Photoelastic Analysis for Two-Dimensional Crack Propagation

本文用动光弹性法分析探讨二维裂纹传播动态特性,用多火花高速照相机记录双悬臂梁试件中裂纹传播的光弹性等差线条纹图,在几个包含从起裂到止裂的试验中取得这些条纹图的试验数据,给出时间对裂纹长度t-a和裂纹长度对动态应力强度因子a-K_Id两组曲线。讨论了运动方程和它的解。给出裂纹传播的裂尖附近的动态应力场和提供一个光弹性估计动态应力强度因子的实用分析程序。从本文解出发,将数值分析等差线条纹图和试验的等差线条纹图对照,可见两者能很好的符合。

In this paper the dynamic behavior of crack propagation in two dimensions is investigated by dynamic photoelasticity. Photoelastic isochromatic fringe patterns associated with cracks propagating in double-cantilever-beam(DCB)specimens were recorded with a high-speed multiple spark camera. Experimental data from these patterns were obtained in several tests to cover cracks propagating from initiation to arrest, from which curves of both time versus crack length t-a and crack length versus dynamic stress intensity factors aK_(Id) were given. The equations of motion and its solution are discussed. A dynamic stress field in near-tip of crack propagation is given and a practical analytical pro-cedure for evaluating stress intensity factors by dynamic photoelasticity is also worked out in this paper. The shape of isochromatic lobes given by calculation based on the present formula agrees well with that obtained by experimental isochromatic patterns.