Design for Internal Quasi-Static Pressures from Partially Confined Explosions

摘要

In the early 1980's, results from a series of tests in a partially confined enclosure were used to develop a prediction model for internal gas pressure. The test variables were Charge Weight, W; vent area, A, and frangible panel weight, w. The gas pressure time history was measured in each test. A semi-empirical prediction model for predicting scaled gas pressure impulse, ig/W1/3 was developed using the Peak Gas Pressure, Pg , and a decay rate based on the instantaneous gas pressure, Pg(t), and vent area Av(t), and the constant scaled parameters: maximum vent area AV/V2/3, W/V ratio, frangible panel weight w/W1/3, and shock impulse on the frangible panel, ir/W1/3. A computer program was written to predict the total quasi-static gas pressure impulse. The program is now named FRANG and is referenced by the tri-service design manual 'Structures to Resist the Effects of Accidental Explosions' (Navy NAVFAC P-397, Army TM5-1300, and Air Force AFM 88-22). The work was presented in at the 21st DDESB Seminar: 'Effect of Frangible Panels on Internal Gas Pressures' by J.E.Tancreto and E.S. Helseth. FRANG is widely used to calculate the internal gas pressure loads on confinement structures.