OS9-1-2 Effect of Out-of-Plane Deformation on Strain Measurement using the Digital Image Correlation Method

Abstract

In order to inspect the strength and reliability of structures, measurement by strain gauge is widely used. However, strain gauges measure only the strain of points where they were attached. Therefore, there is a growing demand for reliable and accurate strain distribution measurement of structures. The purpose of this study is to develop a strain distribution measurement system by the digital image correlation (DIC) method. However, the DIC method has several drawbacks concerning accuracy; the out-of-plane deformation of structures has an adverse effect on the measurement accuracy. In this paper, the effect of the out-of-plane deformation was taken into account. We developed a formula to compensate for the effect of the out-of-plane deformation. We carried out experiments using a translation test and a four point bending test to study the accuracy of the strain distribution measurement by the DIC method. The measured strain distributions were compensated by the proposed formula. It was found that the proposed compensation formula is effective to improve the strain distribution measurement by the DIC.