Finite Strain Kinematics of Multi-scale Material by Digital Image Correlation

In this study, we present a method to analyse experimentally the deformation kinematics of a heterogeneous material using digital image correlation. The periodicity of the microscopic deformation patterns is assessed from the displacement measured along the edges of unit cells. The first order macroscopic transformation gradient is shown to enable capturing the deformation of the unit cell even for large plastic strains. It is also shown that cells along the boundary of the heterogeneous media have a non periodic higher order kinematics.