| 摘要 |
PURPOSE:To enable the accurate measurement of strain even in the case of deformation containing out-of-plane displacement, by providing a laser beam source, a speckle detection means and an operator. CONSTITUTION:The laser beam emitted from laser 6 is allowed to illuminate a measuring point in such a state that a wt. 3 is not loaded on the test piece 1 fixed to a fixing jig 2 and a speckle pattern is detected by first - fourth image sensors 7-10 to be transmitted to and stored in a computer 4. Next, the wt. 3 is loaded on the test piece 1 to generate strain based on deformation in the test piece 1 and the laser beam emitted from the laser 6 is allowed to irradiate the measuring point and a speckle pattern is detected by the first - fourth image sensors 7-10 to be transmitted to and stored in the computer 4 as an electric signal. The computer 4 stores the speckle patterns at four observation points before and after the deformation of the test piece 1 but calculates the mutual correlation function of the speckle patterns before and after deformation in the first - fourth image sensors 7-10 and calculates the movement of the speckles from the peak position thereof. By this method, strain can be measured without receiving the effect of out-of-plane displacement.
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