Experimental and numerical investigation on the dynamic response and damage of large-scale multi-box structure under internal blast loading

Abstract

Internal blast is different from external or air blast for the reason of internal blast load is much more complicated and more destructive to target structures. The present work presents a large-scale experiment on multiple steel box structure under confined blast loading. A multi-box structure specimen with a dimension of 7.5 m × 2.9 m × 2.2 m was designed and field blast test with 1.782 kg TNT detonated inside this model was carried out. The damage features and dynamic response of the specimen were analyzed. The plates near the explosive suffer from strong impact and result in some fragments with high velocity which are destructive to other structural members. Meanwhile, the dynamic response processes were recorded by using the high-speed photography system. The response process of the whole model can be divided into two different stages, namely, localized damage response stage and integral vibration stage. In addition, numerical model considering both double-sided and single-sided fillet welding of this large-scale experiment were built, the dynamic response and the propagation of internal blast wave were analyzed. The numerical studies show that, to achieve a good consistency with the experiment, the failure strain for double-sided and single-sided fillet welding should be set to 0.1 and 0.08 respectively for such large-scale structure under explosive load. Finally, several suggestions for the design of multi-box structure are put forward based on the experimental and numerical investigations.