离面位移数字散斑干涉系统测量材料内部缺陷

Measurement of internal material flaws based on out-of-plane displacement digital speckle pattern interferometry

为了实现对材料内部较深层缺陷的大小和深度的检测,采用弹性理论分析并结合离面位移数字散斑干涉实验的方法,分析了含内部缺陷试件的离面位移分布,并给出了理论解。同时用数字散斑干涉和数值仿真得出试件的离面位移,将3种方法得到的离面位移及其1阶导数的分布做了对比,由对比结果可知,理论、实验及仿真得到的结果非常吻合,并对误差做了分析。从实验得到离面位移的1阶导数可获得缺陷的大小,结合理论计算出缺陷的深度,二者的误差都在允许范围之内。结果表明,利用离面位移数字散斑干涉系统测量材料内部较深层缺陷具有很高的准确性。

In order to detect the size and depth of an internal deep flaw in materials, combining out-of-plane displacement digital speckle pattern interferometry （DSPI） with elasticity theory, the out-of-plane displacement distribution of a plate with an internal flaw was analyzed. Then it was verified by numerical simulation and DSPI. The out-of-plane displacement curves and its first-order derivative curves obtained by the above three methods were compared with each other. It was shown that results obtained from these three methods were in good agreement. The experimental error was analyzed. Finally, the flaw size was calculated from the first-order derivate of the out-of-plane displacement. Both the errors of the experimental and theoretical results were in the acceptable range. The results show that DSPI is suit for detection of internal deep flaws with high accuracy.