AN EXPERIMENTAL STUDY ON THE EFFECTS OF BURST PRESSURE ON AIR BLAST DEVELOPMENT IN A BLAST WAVE SIMULATOR

Due to the extensive use of explosive devices in military conflicts, there has been a dramatic increase in life-threatening injuries and resultant death toll caused by explosive blasts. In an attempt to better understand the blast waves and mitigate the damages caused by such blast waves, various devices/systems have been developed to replicate the field blast scenarios in laboratory conditions. The East Carolina University Advanced Blast Wave Simulator (i.e., ECU-ABWS) is one such facility that can reproduce blast waves of various shapes and profiles. The peak overpressure of a blast is the key factor that causes the greatest number of damages, and it is essentially determined by the burst pressure of the blast. Therefore, a better understanding of the effects of burst pressure on blast generation and development is strongly desired to develop safer and more effective blast mitigation technologies. In the present study, a series of experiments were carried out in the ECU-ABWS to characterize the blast waves generated under different burst pressure conditions. While the incident (side-on) pressures at multiple locations along the blast propagation direction were measured using a temporally-resolved multi-point pressure sensing system, the time-evolutions of blast wave profiles were also qualitatively revealed by using a high-speed Schlieren imaging system. The synchronization of pressure sensing and Schlieren image acquisition enables us to extract more physical details of the dynamic blast wave development under different burst pressure conditions by associating the incident pressures and shock wave morphologies. In this study, the different burst pressures were achieved by altering the thickness of the membrane separating the driver section of pressurized gas and the driven section of air at atmospheric pressure. It is found that there is a linear relationship between the burst pressure and the peak overpressure. As the burst pressure increases (by increasing the membrane thickness), more clearly defined shock wavefronts are also observed along with the peak overpressure increase.