A Challenge for Strain Optical Measurement for Bimetal

A challenge method composed of digital image correlation (DIC) method, circle coordinate grid technology and finite element (FE) software to conduct strain measurement of bimetal is presented. This approach can carry out the prediction and measurement of strain. The coordinate grids are painted on top and bottom surface of bimetal when experiment and simulate specimen. Each node is named a fixed number in turn, and these numbers can precisely help to identify the same name point between FE software and the experiments specimen. The bimetal sheet has been tested using DIC software, circle center of the coordinates points can be accurately identify on the surface of bimetal. The changing of distance between adjacent points is computed to construct the forming limit diagram before and after forming. It is an effective means to evaluate the forming performance of bimetal and verify the reasonable of FE analysis results. 2A12 metal is conducted experiment using the challenge method in this paper, bimetal has not conduct experiment due to some reasons.