Abstract
Mitigation of a blast wave from a straight tube using glass beads was evaluated to examine blast-wave mitigation by glass beads on a tube floor. Glass beads of 0.6 mm or 3.0 mm diameter were installed on the floor of a square, 330-mm-long straight tube with cross-sectional area of 30 × 30 mm2. Arrangement of the glass beads on the tube floor was varied in four ways. The glass bead layer thickness was 5.0 mm, so that the glass beads did not contact with the test explosive. One end of the tube was closed. A specially designed small detonator that contained 100 mg lead azide was ignited near the closed end of the tube as the test explosive. The dependence of mitigative effect on the glass bead diameter and the arrangement was evaluated by measuring the blast pressures outside the tube. The glass beads mitigated the blast wave. The “without glass beads equivalency” analysis revealed that small-diameter glass beads absorbed more energy than large-diameter beads did. The absorbed energy was approximately 40 % of the explosion energy. Results of this study also revealed that the glass beads, which were not near the explosive, are more important for blast mitigation than a water layer on the tube floor.
