Identification of Orthotropic Plate Stiffness Using Open Hole Tensile Test

Identification of mechanical parameters is still a challenge on real structures. With the improvement of optical full field measurement techniques, it becomes easier, but in spite of many publications showing the feasibility of such methods, experimental results are still scarce. We present here a first step towards a global approach of mechanical identification for composite materials. The chosen mechanical test is an open hole tensile test according to standard recommendations. For the moment, experimental data are provided by a moiré interferometry set-up. The global principle of the identification developed here is a minimization procedure, based on Levenverg-Marquardt agorithm. This approach has the advantage to have a high adaptability. In particular, the optical system and the signal processing can be modelized as well as the mechanical aspects. In the paper, different kind of cost functions are tested by using an identifiability criterion. Even if some mechanical considerations can be made, the simpler mathematical form is the more efficient. The used model is an analytical one based on Lekhnitskii approach. Identified values are similar to values from classical mechanical tests within 5 % except for the Poisson’s ratio (15 %).