HIGH ACCURACY MEASUREMENT OF STRAIN DISTRIBUTION |
|---|
| Y. Oshida, Y. Iwahashi, K. Iwata |
- Abstract:
- A phase-shifting speckle shearing interferometer using a TV camera to measure the strain distribution is presented. In this interferometer, two diffraction gratings are used for the spatial shearing and the phase-shifting. A strain is obtained by the spatial differentiation of the in-plane component of the deformation. In this system, the in-plane component of the deformation is obtained by the laser light illumination with two directions that are symmetric with respect to a normal line of the object surface. Spatial differentiation is achieved optically by the interference of two sheared images formed with the diffraction grating. Then, the phase change of the speckle between before and after deformation corresponds to the strain of the object. In order to measure the phase change accurately, a 4-step phase-shifting method is used. The phase-shifting is applied to the sheared diffraction light by moving the diffraction grating. The phase-shifting images are taken in to the computer and the phase change is calculated. As this calculation is done at every point over the object surface, the strain distribution can be obtained accurately. An experiment for measuring a strain of the stretched thin plate is performed with the proposed method, and the strain distribution is obtained.
- Keywords:
- speckle shearing interferometer, phase-shifting method, strain measurement
- Download:
- IMEKO-WC-2000-TC15-P428.pdf
- DOI:
- -
- Event details
- Event name:
- XVI IMEKO World Congress
- Title:
Measurement - Supports Science - Improves Technology - Protects Environment ... and Provides Employment - Now and in the Future
- Place:
- Vienna, AUSTRIA
- Time:
- 25 September 2000 - 28 September 2000