交变应力下冷胀孔边残余应力衰减规律的有损检测试验研究

对高胀孔量下的ＬＹ１２ＣＺ板件孔边残余应力在交变应力作用下衰减规律的有损多试件普通莫尔密栅云纹检测方法进行了尝试,给出了一定载荷范围内残余应力的衰减规律,揭示了高胀孔量下残余应力的再分布现象。研究表明,本文所使用的多试件有损检测方法,不但经济可行,而且有足够精度,应用前景十分广阔。

A DESTRUCTIVE EXPERIMENTAL STUDY OF THE ATTENUATION OF RESIDUAL STRESS AT AND NEAR THE EDGE OF A COLD EXPANDED HOLE UNDER APPLIED CYCLELOADING

The destructive experimental study of such attenuation in the title presents greater dif-ficulties because those specimens expanded by the same process often differ in initial values of residual stresses from one another.Up to now few or no such experimental study has been re- ported in the open literature. An exploration experimental study is proposed for hard-aluminum alloy LY12CZ sheet specimens with a cold expanded(4.23%)hole,using 100 lines/ mm Moire' gratings and with the specimens cut after fatigue test.The cut is perpendicular to the applied load and in parallel with the diaineter of a hole. The distance between the cut and the diameter is 1～ 2mm. In the measurement of a strain,these values at the left and right edges of a hole and those values in a group of specimens are averaged respectively. A satisfactory result of the experiment is obtained.A redistribution of residual stress(in the form of a strain)at the edge of a hole with higher cold expansion under applied cycle loading is presented.