Blast injuries to people inside buildings

When a building is struck by a blast wave, people inside can get injured both from impact of parts from the damaged building and by the pressure transferred into the building through openings. By numerical simulations the pressure inside a building is found for a series of incident blast waves with different values of peak pressure and specific impulse. Then the velocity of the human chest wall is found from the pressure-time histories by Axelsson’s model, and the lethality is estimated from the maximum chest wall velocity. The results from the simulations show that in concrete structures the blast injury is significant compared to injury from building debris at incident pressures down to 500 kPa. The lethality can be estimated by PI-curves fitted to the results. In wooden constructions the injury from building debris is much larger, and the blast injury can be neglected for incident pressures below 3 MPa. Simulations of blast tests against a construction in scale 1:25 give inside pressure values in good agreement with the tests. Experiments in full scale and in scale 1:5 are also fairly well simulated. The results show that modelling windows as rigid bodies is a good approach when the pressure load is considerably larger than the window capacity. An experimental verification of the similar approach for the front wall is also achieved.