Modeling of Impacts on Sandwich Structures

In aeronautics, passenger safety and reliability of structures are essential aspects. Helicopter blades are particularly sensitive to impact solicitations but modeling these phenomena is still difficult and experimental tests often replace the prediction. This study will be focused on the modeling of an impact on the skin of the blade. It is equivalent in a first approach to an impact on a sandwich panel made up with a foam core and a thin composite skin. The objective is to develop a representative model of the damage kinetics adapted to the modeling of the complete structure. Thus, an F. E. explicit model has been developed. It relies on the development of a multiscale approach. Damage is modeled at an intermediate scale (mesoscopic) in order to reproduce the damage kinetics observed at a microscopic scale. Numerical results obtained are correct and reproduce the behavior of the panel for a static test of indentation and low velocity impact test.