Accurate internal deformation measurement of an indentation test using micro-CT and self-adaptive digital volume correlation.

Abstract

Mechanical indentation testing is a widely used technique for determining local mechanical properties of materials. Accurate measurement of internal deformation in the indentation test is necessary for further study of material properties. Therefore, an in situ experimental measurement strategy combining micro-CT imaging and self-adaptive digital volume correlation (SA-DVC) is proposed. Unlike conventional DVC, SA-DVC can automatically identify the optimal subvolume size for each calculation point, which can effectively minimize measurement errors. The efficacy of the proposed method is first verified by the simulated indentation experiment. Then, it is used to analyze the deformation of epoxy resin composite in a real indentation experiment. Measurement results indicate that the proposed method can estimate three-dimensional displacement and strain fields with enhanced accuracy, and further application of the obtained measurement results on material parameter identification and stress field reconstruction is expected.