Finite Element Stereo Digital Image Correlation Measurement for Plate Model

The aim of this study is to measure accurately the boundary conditions, namely the displacements and rotations, along the edges of a large part of a composite panel subjected to complex loadings. With classical Stereo Digital Image Correlation techniques (Stereo DIC), the displacement field can only be measured on the upper skin. The rotations are usually estimated a posteriori by numerical differentiation and smoothing. Unfortunately additional uncertainties may arise with these steps. Conversely, the use of a Finite Element plate model is proposed here to regularize a Stereo Finite Element-DIC measurement (Stereo FE-DIC). The idea is to use the 3D displacement as the primary unknown of the correlation problem. This approach thus requires projection operators (here based on a pinhole camera model). It allows taking into account distortions directly.