Air-blast Analyses Methodology for Urban Areas

The damage to buildings in an urban area from conventional weapons and improvised explosive devices is of great concern for vulnerability studies. One major concern is the air blast propagation in an urban area, with local building geometry strongly influencing the air blast's pressure-time history due to the reflection of the blast wave within the urban area. Furthermore, the damage level for a building decreases rapidly with its distance to the detonation. An accurate determination of the structural response of a building subjected to an air blast loading from a high explosive detonation requires a great effort, since models for both air blast propagation and structural response needs to be verified. Different numerical methodologies for far-field air blast propagation are evaluated in this study. The Overture partial differential equation (PDE) and LS-DYNA CE/SE solvers are considered suitable for future studies of far-field air blast propagation. These two solvers have different limitations and these needs to be considered when a modelling technique is chosen for a specific problem. The advantage with the LS-DYNA concept is that structural response of a building can be incorporated within the model, since advanced structural modelling techniques and also advanced material models are available with this code. The adaptive mesh refinement within the Overture PDE solver package on the other hand shows promising development capabilities for far-field air blast analyses. However, further work is needed to further evaluate its capabilities for more realistic air blast scenarios, e.g. analyses of the multiple building scenario that was analysed with the LS-DYNA solvers.