Multiwavelength shearography for quantitative measurements of two-dimensional strain distributions.
Multiwavelength shearography for quantitative measurements of two-dimensional strain distributions.
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DOI：
10.1364/ao.38.000096
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发表时间：
1999
期刊：
影响因子：
1.9
通讯作者：
R. Kaestle;E. Hack;U. Sennhauser
中科院分区：
文献类型：
--
作者：
R. Kaestle;E. Hack;U. Sennhauser
本文报道了一种用于测量二维应变分布的多波长散斑剪切干涉仪。该系统基于用三个二极管激光器同时照射物体，所述二极管激光器以800和850 nm之间的不同波长发射。波长分离和图像采集进行了一个特殊的光学安排，包括窄带通滤波器和三个黑色和白色相机。具有可变剪切元件的剪切照相机，结合适当的照明几何形状，使我们能够从相位步进条纹图案中分离出所有六个位移导数。通过两个不同的实验验证了光学系统和测量过程。首先，剪切传感器头用于确定面内位移，和，第二，面内应变分布的铝块引起的温度膨胀进行了测量。
We report on the development of a multiwavelength speckle pattern shearing interferometer for the determination of two-dimensional strain distributions. This system is based on simultaneous illumination of the object with three diode lasers that emit at different wavelengths between 800 and 850 nm. Wavelength separation and image acquisition were performed with a special optical arrangement, including narrow-bandpass filters and three black-and-white cameras. The shearographic camera with a variable shearing element, in combination with the appropriate illumination geometry, permitted us to isolate all six displacement derivatives from phase-stepped fringe patterns. The optical system and the measurement procedure were validated with two different experiments. First, the shearographic sensor head was used for the determination of in-plane displacements, and, second, in-plane strain distributions of an aluminum block caused by temperature expansion were measured.