Modelling the Effects of Blast Loads in Rail Vehicles

This thesis describes the development of modelling techniques to understand the effects of an Improvised Explosive Device on the passengers and structure of a rail vehicle. The work aims to establish if rail vehicle design could influence the distribution of passenger injuries within a rail vehicle. Finite element models were used to predict the detonation and propagation of the blast pressures, and the structural response of a rail vehicle.
Models were developed to allow the prediction of human injury, using validated work from the open literature and from basic principles. After a detailed review of existing work on injury, chest injury from blast pressures and penetrating injuries from high speed projectiles were chosen as the injury modes to be included in the model.
To provide data to validate numerical models, experimental blast testing in confined geometry was undertaken. Four configurations of a test cell were used to gain an understanding of the effect of vertical baffles on pressures and cumulative impulse. Excellent correlation was seen between test shots in each arrangement. Baffles were seen to increase the cumulative impulse seen at the wall opposite where they were fixed, although the number and spacing of them was seen to have no significant effect.
Numerical modelling of the experimental test arrangements showed good correlation between the experimental pressure time history data and the numerical predictions. Secondary combustion was considered using an energy release function, after which cumulative impulse calculated from experimental data were was predicted by the numerical models.
Risk prediction and finite element models were combined to model the effects of an IED blast in a representative rail vehicle. A number of key variables were studied, and it was identified that although rail vehicle design can affect the injury severity, passenger spatial density was the driver for determining the distribution of injuries.