Weapons Effects FRMs for Contact or Embedded Detonations in Fixed Targets

ABSTRACT:This SBIR Phase II Project has as its objective to develop High-Fidelity Physics-Based (HFPB) Fast-Running Models (FRMs) for simulating the effects of small weapons in fixed urban targets constructed from reinforced concrete, masonry, and brick. The FRMs are intended for predicting breach characteristics such as hole volume and profile, the stochastic secondary debris generated by the breached material and spall, residual wall damage and structural functionality, and estimates of residual airblast which propagates into the building. The FRMs are based on highly detailed HFPB models which simulate several key physics regimes which occur between the instant of inert impact of a weapon on a target component such as a wall and the final development of breach shape and low velocity secondary debris fly-out. In the Phase I and in earlier work the project team has hierarchically validated the HFPB modeling approach by both laboratory and field tests, including full-scale comparisons with experiments conducted by JLF over several years. The validated HFPB simulation technology is used to populate training spaces appropriate for the various target types and weapons with virtual data to develop and calibrate the FRMs, which are intended for integration into MEVA.BENEFIT:Urban operations have become increasingly important to the military planners. Urban operations frequently require additional theatre considerations, such as verifying that specific tactics will minimize harm to civilians, friendly forces, and unaffiliated structures in the area. Such precautions exclude the use of large weapons and therefore military planners must focus on the use of smaller weapons. These small weapons are often used to breach urban walls and can be inert projectiles or explosive projectiles (cased weapons) that detonate upon impact or are set for a delayed detonation during partial penetration in order to maximize damage. The physics of the impacts and the resulting breakup and debris generation of these munitions is very complex and the number of urban scenarios extremely large. The uncertainties are also very large. The class of HFPB models that can simulate the complex phenomena and variability involved requires vast computer resources and skilled personnel to setup and run the models; such an option is not suitable for military planners and commanders who need rapid answers. Therefore it is necessary to develop FRMs that capture the necessary outputs and predictive uncertainty of the HFPB simulations but which nonetheless run very quickly. For example, commanders might like to know what munitions to use and where to impact a wall of a particular construction material (e.g., concrete) in order to breach the wall and create a hole that will enable access into a building. They might also require estimates of debris lethality to people and infrastructure. The fast-running models developed in this project will benefit military planners by supporting these kinds of decisions well beyond any current capabilities.