Numerical investigations on the dynamic response of steel plates subjected to near-field explosions using a two-stage uncoupled approach

Abstract

The dynamic response of structures subjected to blast loading has long been a concern in the blast engineering community. Steel plates are widely used in various structures (e.g. buildings, bridges, ships and vehicles). Recently, a two-stage uncoupled numerical approach (2Stage-DI) was proposed by Rigby et al. [1] to predict the plate response for near-field scenarios. This study aims to evaluate the two-stage uncoupled approach for the prediction of the dynamic response of blast-loaded plates with respect to the applicable scaled distance range. In addition, it provides insights into the effects of the plate shape, dimension and thickness on the applicable scaled distance range of the 2Stage-DI model, offering practical guidelines for the blast-resistant design. Three different types of numerical models are developed, i.e. the fluid-structure interaction (FSI) model, the two-stage uncoupled models with distributed impulses (2Stage-DI) and uniform impulses (2Stage-UI). Unlike the 2Stage-DI model, the 2Stage-UI model adopts the energy-equivalent impulse for the conversion of the nodal velocities, which are uniformly distributed over the plate. The FSI and 2Stage-DI models are validated against the test data of three experiments. After that, the validated FSI models are used as the reference to evaluate the applicable scaled distance range of the 2Stage-DI models for steel plates of different shapes (square and circular), dimensions and thicknesses. Several important conclusions are drawn from this study. Firstly, the 2Stage-DI model is significantly less time-consuming than the FSI model. Secondly, the circular plate has a broader applicable scaled distance range of the 2Stage-DI models than the square plate with the same surface area. Thirdly, the applicable scaled distance range of the 2Stage-DI model expands when the plate dimension (length or diameter) increases. Fourthly, the applicable scaled distance range of the 2Stage-DI model is first increased and then decreased with the thickness. Lastly, the 2Stage-UI models, which are based on the equivalence of the kinetic energy of the steel plates, are also feasible to predict the plate response for near-field scenarios.