基于数字图像相关法的多尺度全场应变测量方法

To realize strain measurement accuracy at different scales，a multi-scale full-field strain measurement method based on digital image correlation (DIC) was proposed. A multilayer speckle preparation method was developed，and the quality of speckle was verified by numerical simulation test. The out-of-plane displacement was quantified by wedge plane model，and a false strain correction method based on lens imaging model was proposed. The calculation methods of out-of-plane displacement and the method of false strain correction were verified by relevant experiments. The results indicated that the average error of the surface displacement calculation method was less than 4.20%; compared with the traditional DIC method，the accuracy of strain measurement by using the false strain correction algorithm was improved by more than 8.16%，achieving high-precision measurement of multiscale full-field strain.