The Resistance of Sandwich Cylinders With Density-Graded Foam Cores to Internal Blast Loadings

Abstract The resistance of sandwich cylinders with density-graded foam cores to internal blast loadings is investigated theoretically and numerically. Four kinds of density-graded foam core are designed, such as positive, negative, middle–high, and middle–low gradients. The deformation process of the sandwich cylinders is assumed to be split into three phases, i.e., fluid–structure interaction, combined deformation of core and inner wall, and sandwich stage of motion. Employing a rigid perfectly-plastic locking model of density-graded foam core, analytical models are proposed to predict the dynamic response of gradient sandwich cylinders. Finite element simulations of gradient sandwich cylinders subjected to internal blast loadings are carried out and agree well with the analytical predictions. Furthermore, the effects of the core density gradients and the wall thickness distributions on the blast resistance are explored and identified. It is shown that the thicker inner wall design can enhance the blast resistance of sandwich cylinders with the same mass.