应用干涉法测量杨氏弹性模量

Application of Interference in Young's Elastic Modulus Measurement

将空气劈尖的等厚干涉原理与CCD图像处理技术相结合,提出了一种对材料杨氏弹性模量进行高精度自动测量的新方法。该方法利用待测试件受力产生的形变改变空气劈尖顶角,并用一元线性回归方法对CCD的像元序号与所接收到的干涉条纹光强极大值序号之间线性关系进行拟合,进而确定出空气劈尖顶角大小。由导出的杨氏弹性模量与空气劈尖顶角变化量之间的关系,对待测试件的杨氏弹性模量进行了计算。测量结果表明,新的测量方法是可行的,测量相对误差为1.5%,而且测量系统具有高精度、高灵敏度的特点,可广泛应用于各种微小形变的测量。

With the combination of the wedge and CCD image-processing technique, a principle of the equal thickness interference of air high precision automatic measurement method for Young＇s elastic modulus is presented. The deformation of the forced specimen is used to change the air wedge angle. The air wedge angle can be computed with application of the unitary linearity regress method in fitting the relation between the serial number of the CCD pixels and the serial number of the intensity maximum of interference fringes. Young＇s elastic modulus of the testing object can be calculated by the relation between it and the change of the air wedge angle. The experiment result proves the feasibility of the new method. The relative error of Young＇s elastic modulus is 1. 5%. Besides, the measuring system has the characteristic of high accuracy and sensitivity, and can be widely used in measuring the various small deformation.