基于激光技术的压痕应变花及测试应变的原理

Indentation strain rosette and the principle used for measuring strain based on laser technique

介绍了一种用于测试面内三个应变分量的应变测量技术,在试件表面预先压制三个压痕,通过激光照射压痕,经衍射后干涉,产生干涉图。通过分析变形前后干涉斑点的光强值的变化来对待测位置进行应变测量。实验表明该方法对待测试件表面损伤小,且压痕应变花尺寸小,是一种新的光学应变测试技术,不仅可以用来进行普通应变测量,尤其对解决小空间应变测试问题有其独特的优点。

A new strain measurement technique used to measure three strain components in plane is introduced. Three indentations are made in the surface of specimens before experiment~ A laser beam impinges up on the specimen with indentations. Through diffraction and interference of beam, six interference patterns are obtained. Analyzing the light intensity change of before and after deformation of specimen, three strain components are obtained. The micro indentation strain rosette method is a new strain measurement technique according to the experiment. Because of small dimension of indentations, little damage is taken place for specimen. The method not only can be used for general strain measurement, but also can be used for micro area strain measurement.