Elastic wave propagation in hexagonal honeycomb sandwich panels: Physical understanding and numerical modeling

This paper gives theoretical and numerical analyses of elastic wave propagation phenomena in sandwich panels with a honeycomb core, especially when the frequency domain of interest is large and involves high frequencies. In the literature, computational models represent rather these panels as an equivalent homogeneous continuum using shell type finite element mesh than use a detailed "geometrically exact" finite element mesh. The reliability of such homogenized models is critically dependent upon the pertinence of the homogeneous constitutive model and the shell kinematics, as far as the shortest wavelength to consider is smaller than the size of honeycomb cells and than the shell thickness. Herein, it is proposed to discus this issue and to qualify the classical homogeneous models and one- or multi-layered shell kinematical models with respect to the frequency domain of interest. The quality assessment is made by comparison with both numerical simulations of a small detailed geometrically exact finite element model and experimental results on a large sandwich plate. Several criteria of qualification in terms of energy and/or displacement are considered