Numerical study of blast mitigation performance of folded structure with foam infill

Blast mitigation capacity of sacrificial cladding with foam filled open-top Truncated Square Pyramid (TSP) is investigated in this study. Quasi-static crushing tests of the TSP foldcore with two different shapes of rigid Polyurethane (PU) foam as infill are carried out. Numerical model of the crushing test is then constructed and validated using the test data. The calibrated models are then used to evaluate blast mitigation performance of sacrificial cladding with the proposed structures as core. Structural response and blast mitigation performance of two proposed foam filled TSP foldcores are compared with the case without foam infill under various blast scenarios. Peak load transmitted to the cladding protected structure during blast loading is set as primary criterion to evaluate the cladding performance, other parameters such as centre displacement and energy absorption are also selected as criteria. Due to the foam-wall interaction effect, foam filled TSP foldcore shows an effect of 1 + 1 > 2 under quasi-static crushing. The proposed TSP foldcore with shaped foam infill has superior quasi-static crushing resistance than the summation of stand-alone TSP foldcore and PU foam infill. When subjected to low intensity blast loading, shaped foam filled TSP foldcore shows similar blast mitigation performance to the case without foam infill in terms of the peak transmitted force. However, under high intensity blast loading, the initial peak transmitted force to the protected structure can be greatly reduced by cladding with foam infilled TSP foldcore.