Identification of the local stiffness reduction of a damaged composite plate using the virtual fields method

In the present study, a damage detection problem is formulated as the identification of the spatial stiffness distribution in a damaged composite plate. Full-field heterogeneous curvature fields obtained from an optical deflectometry technique are processed by using the virtual fields method adapted to retrieve the 2D stiffness distribution map of a damaged carbon-epoxy plate. The method not only picks up the location of the damage but also provides a fairly good estimate of the stiffness reduction in the damaged area. In this paper, the procedure is described, validated on simulated measurements and some initial experimental results are given.