Deformation measurement of mesh-hole structure based on digital image correlation

Abstract

The mechanical properties of structures after lightweight design should be taken seriously. However, after optimization, it is often difficult to measure its mechanical properties due to the complex structures of mesh-hole. Based on digital image correlation (DIC) and binocular stereo vision, a full-field deformation measurement method for the surface of mesh-hole structures under stress is proposed. Firstly, by utilizing the grayscale information entropy of the foreground and background, the speckle calculation region on the reference image is automatically extracted. It avoids ineffective calculation of non-measured areas. Secondly, for the complex deformation of structure with holes, two second-order deformation parameters are introduced to describe the grayscale mapping between the reference subset and the deformed subset. The corresponding correlation matching algorithm is also improved. Thus, it ensures computational efficiency while enhancing matching accuracy. Finally, the mesh-hole structure is printed with polylactic acid (PLA) material, and its compression deformation is measured. The results indicate that the method proposed can be used for rapid tests of the mechanical properties of lightweight structures.