Blast Effects from Cylindrical Explosive Charges: Experimental Measurements

Abstract : This report presents results of an experimental study of free-air blast wave properties for end-initiated cylindrical explosive charges. The study was motivated by the need for data on positive impulse form cylindrical charges, as a function of charge length/diameter (L/D) ratio, distance, and angle from the charge axis. Cast cylindrical charges of Pentolite were used, with L/D ratios of 1/4, 1/2, 1/1, 2/1, 3/1, 4/1, and 6/1. In all, 64 charges were fired: 54 8-pound cylinders, 4 16-pound cylinders, and 6 7/8-pound spheres (used for internal calibration purposes). For each shot, blast parameters were measured at two angles, 90-degrees apart, using six pressure gauges at each angle. Gauge arrays extended from 7 feet to 31 feet from the charge, covering a nominal pressure range of 100 psi down to 3 psi. Pressure-time plots from all guages on all shots are presented, together with measured values of peak pressure, positive impulse, positive duration, and time of arrival. Graphs of the variation of peak pressure and impulse with L/D ratio and angle are presented together with a comparison with spherical charge data. Substantial differences between blast waves from cylindrical and spherical charges are observed. Also presented are the results of scaling tests, an error analysis, and recommendations for further work. (Author)