The response of clamped sandwich plates with lattice cores subjected to shock loading

The dynamic response of clamped circular monolithic and sandwich plates of equal areal mass and thickness has been measured by loading the plates at mid-span with metal foam projectiles. The sandwich plates comprise AISI 304 stainless steel face sheets and either AL-6XN stainless steel pyramidal core or AISI 304 stainless steel square-honeycomb lattice core. The resistance to shock loading is quantified by the permanent transverse deflection at mid-span of the plates as a function of projectile momentum. It is found that the sandwich plates have a higher shock resistance than monolithic plates of equal mass, and the square-honeycomb sandwich plates outperform the pyramidal core plates. Three-dimensional finite element simulations of the experiments are in good agreement with the experimental measurements. The finite element calculations indicate that the ratio of loading time to structural response time is approximately 0.5. Consequently, the tests do not lie in the impulsive regime, and projectile momentum alone is insufficient to quantify the level of loading.