光栅应变法的误差分析与改进

Error Analysis and Improvement on the Grating Strain Method

将光栅制作于试件表面作为应变传感器，激光束照射试件被测点所产生的衍射图案随该点的变形发生变化。测定衍射图案的变化可以直接计算出被测点的变形。本文分析了该方法中公式简化、离面转角、离面位移引起的误差，结果表明后两个因素的影响不容忽视。本文还对误差的减小和消除进行了讨论。

A grating made on the surface of a specimen can be used as the strain sensor. When alaser beam is injected on it, we can determine the deformation at the measured point by observingchanses of the diffraction pattern from the grating,In this paper the errors of this method caused bysimplification of formula,out- plane rotation and out-plane displacement are analyzed. The resultsshow that the influence of the last two fsctors can't be neglected. We also give a discussion on thereduction and elimination of the errors.