Quantity-Distance Requirements for Earth-Bermed Aircraft Shelters

摘要

The subject work has been performed under Phase I of an SBIR (small businessinnovative research) program sponsored by Tyndall AFB. The effort concentrated on development of methods to quantify debris hazards from accidental explosions inside earth-bermed and unbermed aircraft shelters. The Phase I effort addressed shock loading, gas loading, debris breakup, and debris throw. The prediction model, Quantity-Distance Requirements for Aircraft Shelters (QDRACS), includes new programming which uses image charges and ray-tracing of shocks for the specific geometry of an aircraft shelter. Interior surfaces are divided into a grid of rectangular elements. Shock loads are calculated at each element for up to 20 munition stacks. Existing data were utilized to determine structural breakup dependence on load intensity and the formation of small or large debris. Venting is calculated using the FRANG program as a subroutine to QDRACS, but with special treatment for defining vent area and vent perimeter based on the breakup pattern, and venting provided by the door. The velocity of all missiles is calculated based on contributions from both the shock and gas pressure loading. Debris dispersion is calculated using MUDEMIMP as a subroutine. Model results were compared to the Q-D criteria based on DISTANT RUNNER tests. Hazard distances for Event 4 were predicted within 20 percent, and for Event 5, within 5 percent of the DISTANT RUNNER data.