Study of Debris Throw and Dispersion After Break-up of Reinforced Concrete Structures Under Internal Explosion

摘要

DSTA and NTU have been working together to develop a methodology to simulate the breakup and debris throw of reinforced concrete (RC) structures under internal explosion. The numerical simulation simulates the following phases of responses: internal explosive loading; structural breakup and debris launch; debris primary trajectory and post-impact roll-and-bounce. In last DDESB seminar, our findings on structural breakup process were reported using node-splitting method (1). In this paper, the focus is on the phases following the structural breakup. As a result of a structural breakup, debris pieces of different sizes are formed and propelled by the blast/gas pressures. When the overpressure subsides, the debris pieces fly under the action of gravity and the air drag. Very often, the debris does not settle at its first landing position. Instead, it impacts the ground and then bounces off and rolls, or even breakup into several smaller pieces. This paper presents the investigation on all these post-breakup processes, including the effects of drag coefficient on the trajectory. Results are plotted in the format of debris dispersion map. Data collected from the Kasun field tests (2) are used for verification. In general, the simulation results are in good accord with the field test results.