Predicting Structural Debris and Secondary Air-Blast

The secondary debris generated during the breakup of walls and slabs interacts with the high pressure gases passing through cracks in the separated material. This interaction causes a reduction of blast/gas loads in the blast room and acceleration (and sometimes further breakup) of secondary debris that can be lethal to personnel and equipment in adjoining rooms. The secondary debris can also impact walls and windows in adjoining rooms causing additional damage. Current High-Fidelity Physics-Based (HFPB) Fast-Running Models (FRM) ) that are used to predict weapon effectiveness do not model these coupled, interactive physics yet data from current operations in Iraq, Afghanistan, etc. demonstrate that this secondary debris is an important damage mechanism. Ignoring this will have a negative impact on collateral damage estimation and weaponeering activity. A novel approach to simulate this complex scenario using HFPB methods is proposed. FRMs will be developed based on the results of a suite of these HFPB runs BENEFIT: Present HFPB (High Fidelity Physics Based) FRMs (Fast Running Models) at Air Force assessment codes were developed using uncoupled calculations. Therefore, they are not capable of predicting the generation of secondary debris mass-velocity distributions accurately. The current models also do not predict the projection of blast loads to adjoining spaces. The successful completion of this project will provide, AFRL with better tools to account for secondary debris for assessing lethality of weapons.