Indentation response of sandwich panels with positive gradient metallic cellular core

This paper deals with the plastic indentation of sandwich panels with positive gradient metallic cellular core under a spherical indenter. The gradient metallic cellular material has an increasing plateau stress. Under quasi-static compression, the crushing stress of gradient metallic cellular material cannot be assumed as a constant like that of homogeneous metallic cellular material before densification. To predict the crushing stress of the gradient metallic cellular material, a novel predicting formula associated with densification strain is presented. And then a gradient analytical model for the sandwich panel with positive gradient metallic cellular core under the spherical indenter is developed based on the analytical model for sandwich panel with homogeneous core. Finite element simulation is carried out in order to verify the analytical results. The influence of positive gradient metallic cellular core on the indentation force of the sandwich panel is further analyzed.