Experimental investigation on the performance of PVC foam core sandwich panels subjected to contact underwater explosion

Abstract This paper presents a blast experiment to investigate the performance of sandwich panels with metallic face sheets and ungraded/graded polyvinyl chloride (PVC) foam cores subjected to contact underwater explosion. The deformation and failure modes of the sandwich panels were identified and classified. The protective effect of sandwich panel was also evaluated by setting a witness plate. Particular attention was concentrated on the effects of the charge weight, face-sheet configuration, core height, and core gradation. Experimental results reveal that the panel front face suffered severe petalling failure and generated structural fragments; the PVC foam experienced spider-web-like crack failure and perforation failure; while the back face failed into petalling mode or plastic deformation without fracture. The increase of charge weight worsened the panel failure level as expected, yet did not affect the failure mechanisms. Adopting a thick core would benefit sandwich panel in terms of both the energy absorption enhancement and the damage level reduction. The panel system with a thick back face and a thin front face performed better in protecting the witness plate than the one with reverse configuration. Moreover, through designing the graded core with high/middle/low configuration, the panel performance could be further improved.