Numerical modeling of elastic wave propagation in honeycomb sandwich panels under moving loads : application to space launcher

International audienceThis paper gives theoretical and numerical analyses of elastic wave propagation phenomena in honeycomb sandwich panels, especially when high frequencies are involved and wavelengths become as small as the size of honeycomb cells. The honeycomb sandwich panels considered here are made of two thin and stiff fiber-reinforced and stratified shells that are bonded to a thick and lightweight thin-walled core with in-plane two-dimension periodic hexagonal cellular structure. In the literature, computational models generally represent those panels using a shell finite element of an equivalent homogeneous continuum rather than using a detailed geometrically exact finite element mesh. The reliability of such homogenized models critically depends upon the pertinence of the homogeneous constitutive law and the choice of shell kinematics. Unfortunately, this is not straightforward in the context of space launchers, as far as high frequencies are involved and the shortest wavelength of bending waves is smaller than the size of honeycomb cells and than the shell thickness. Herein, we propose to qualify the classical homogeneous constitutive law and thick shell kinematics with respect to the frequency domain of interest defined by the CNES. Criteria of qualification in terms of energies, accelerations, and wave propagation velocities are proposed and considered. The numerical modeling of shock wave propagations using detailed geometrically exact finite element mesh of the honeycomb core is performed to provide reference solutions