Abstract: Based on the existing three-stage theoretical framework, a theoretical analysis is developed to predict the dynamic response of sandwich panels with cellular metallic cores under impact loading by incorporating a yield locus considering the bending and stretching as well as the strength of the core. The central point permanent deflection of the back face-sheet is considered as an index to evaluate the crashworthiness of sandwich structures. In this analytical solution, the whole response of the sandwich panel is split into three sequential stages：fluid-structure interaction, core compression, and overall bending and stretching. The impulse is assumed to be a uniform distribution over the impact area in the first stage. The metallic foam core is considered approximately to be a progressive compressive mode in the second stage, until the face-sheets and core obtain an equal velocity. In the final stage, a classical monolithic plate theory based on an energy dissipation rate balance approach is employed; the maximum back face-sheet central point deflections and response time are obtained by incorporating a comprehensive yield locus. A reasonable agreement between the theoretical predictions and experimental results is found. The proposed theoretical model is helpful to guide the crashworthiness applications of cellular metallic sandwich structures.

Key words: sandwich panels;cellular metals;lightweight;crashworthiness;dynamic response