On the Role of Modeling Dust Production by Fragmenting Warheads in Storage Facilities

The paper presents the results of a coupled Computational Fluid Dynamics (CFD)/Coupled Structural Dynamics (CSD) simulations of cased charges internal detonation within reinforced concrete chambers; a part of a test and modeling effort studying air blast propagation through breached walls. Initial simulations calibrated the CFD/CSD model and determined the physical mechanisms controlling internal blast environments, wall breach, and blast propagation through the breach. In the test, the detonation room (composed of two test walls and two culverts) incurred significant damage due to the fragments and blast loads. Both culverts failed. Initial coupled CFD/CSD simulations modeled the culverts as non-responding surfaces. These simulations reproduced the damage to the test walls, but the pressure histories matched the experimental data only out to ~10 ms. Subsequent airblast reflections were significantly reduced. Post-test damage analysis showed significant fragment damage to the culverts, with the concrete stripped to the first layer of rebars. Repeat simulations, where the culvert response, dust production and dust absorption of kinetic and thermal energy were modeled, matched the experimental data. Additional simulations provided a synthetic database for fast running model development (FRM). These includes modeling of breaching (size and timing), secondary debris, and blast propagation through the breach opening. INTRODUCTION The simulations presented here are part of a test, analysis, and modeling effort investigating airblast propagation through breached walls. The coupled CFD/CSD simulations are providing additional insight and details not measured in the tests, as well as developing a synthetic database to supplement the test matrix.