Experimental investigation on the performance of PVC foam core sandwich panels under air blast loading

The performance of sandwich panels with metallic face-sheets and polyvinyl chloride (PVC) foam ungraded/graded cores under air blast loading was investigated experimentally. In present paper, the performance of interest included the permanent deformation, failure modes and the associated mechanisms underlying the overall response. The majority of the paper was concentrated on the effects of geometric parameters and core gradation on the blast performance of panels. Experimental results showed that regardless of the panel configuration considered here, the panels exhibited a localized dishing deformation of front face and a global dome deformation of back face. The way to achieve a more effective design against air blast is to increase the thickness of the face sheet towards the blast rather than the other sheet. The panel system with a low-density (large thickness) core appeared to be favorable for the mitigation of back face deformation and core cracking failure. Effect of core gradation indicated that placing the low density material at the third core layer and the high density material at the second core layer, thus reducing the momentum transmitted to back face and increasing the crushing deformation of graded core, helped enhance the blast resistance of panel. Furthermore, the comparisons of blast performance between ungraded sandwich panel and graded panels were made. It turned out that overall graded panels did not always outperform the ungraded panel. An optimal core gradation would bring benefits for blast resistance in terms of the face sheet deformation and core cracking failure, but also was required to face the risk of delamination failure.