扩展裂纹尖端奇异场的实验研究

EXPERIMENTAL GH SINGULARITY FIELD AROUND GROWING CRACK TIP

摘要: 用云纹方法测量了 LY12-M 铝材,双边裂纹试件、扩展裂纹沿 x和y方向位移场u_x,u_y。实验的裂纹尖端奇异场与 GH 理论奇异场进行了比较。两者偏差在±10％范围内,得到实验的 GH 奇异场范围与形状。实验证明:扩展裂纹尖端场有(lnA/r)~(α+1)奇异主导区。该主导区形状由腰子形向扁圆、圆形过渡,接近裂纹扩展时形状不规则。在 GH 主导区内,裂纹尖端附近有一个三维贲形,材料损伤区。在该区内 GH 奇异性不存在。

Abstract: The displacement fields ux,uy of growing crack tip for LY12-M material specimens with double edge cracks are measured using Moire method. The experimental singularity fields are compared with GH theoretical field. The size and shape of the experimental GH singularity fields are obtained. The di screpancy of experiment and theory is within ±10%. The experiments show thatthere is (InA/r)α+1 singularity dominant around growing crack tip. The shape of thisregion of dominant singularity are batterfly wing, then ...