Modelling blast loads in rail vehicles

Abstract

The open, accessible and crowded nature of urban mass transit networks has attracted previous attacks in London, Madrid and other cities, and it is very difficult to prevent an attacker entering while retaining normal operation of the system. The research presented here contributes to the modelling capability needed to apply a 'passive safety' approach in vehicle design, whereby the impact and consequences of a blast in a mass transit vehicle could be reduced.The multi-material Arbitrary Lagrangian Eulerian (mm-ALE) approach with Fluid Structure Interaction (FSI) is widely reported in the literature, but has been seen as requiring to fine a mesh to be applicable to large scale structures. Reductions in computing cost and improvements in the speed of finite element codes allows large ALE models to be solved, and mm-ALE approach is shown to be effective at predicting the effects of explosions. Also studied is the recently implemented 2D to 3D mapping function available in LS-Dyna, and comparisons are made with the standard 3D approach in terms of computational expense and solution accuracy.

Characterisation of blast loading in complex, confined geometries using quarter symmetry experimental methods

“…The experimental testing presented here was undertaken with a number of aims in mind: first, to generate data for validation of numerical modelling [1]; secondly, to develop an experimental method using quarter symmetry and scaling to reduce the test and charge size needed, increasing the number of configurations which could be tested in a given time and cost; thirdly, to understand the effect of changes in enclosure geometry on measured pressure and impulse; and lastly to generate data showing the consistency of output from high explosive detonations in confined spaces that can pro-vide the basis for future validations of a variety of prediction tools.…”