Statistical Analysis of Blast Wave Decay Coefficient and Maximum Pressure Based on Experimental Results

Abstract

Various expressions have been given in the literature for calculating blast wave parameters. Without experimental testing, it is difficult to determine which expression will predict the actual measurements more realistically. In this paper, a statistical analysis of two blast wave parameters, maximum overpressure and pressure-time diagram decay coefficient, was conducted based on field tests of the cylindrical TNT charge free-air detonation. Simple numerical simulation was also performed in order to compare the obtained maximum overpressures with the field test measurements. A comparison of the maximum free-field overpressures provided insights on the influence of the air mesh size as this proved to be a critical parameter. Statistically obtained blast wave decay coefficient and the maximum overpressure was compared with the analytical expressions given by different authors to determine the most appropriate description of experimental tests. Expressions are given depending on the scaled distance, i.e. the ratio of standoff distance to measuring sensors and cubic root of the charge mass. Expressions for blast wave parameters are used for a quick approximation of blast load for further analysis of structural elements, so their accurate determination ensures more realistic blast analysis and safer design.

Analysis of Charge Shape Influence on Blast Pressure

“…The pressure sensor distance was kept constant throughout each subsequent detonation, to maintain consistency in the measured data. The blast wave incident and reflected pressures were Based on previous experience in field blast tests [10], to prevent fireball influence, the charges were not placed too close to the sensors. Fireballs can affect sensors at a distance of 0.835 m (Z = 1.8 m/kg 1/3 ), so these tests utilised larger distances.…”

Toward Improvements in Pressure Measurements for Near Free-Field Blast Experiments

“…Most often, papers relying on such experiments only deal with some parameters determined from the signals, such as maximum overpressure peak, or positive phase impulsion, under the form of a synthesis of results, but rarely show the temporal signals from which the data have been extracted. Lukić et al show a statistical analysis of two blast wave parameters, maximum overpressure and pressure-time diagram decay coefficient, based on 21 field tests of the cylindrical 100 g TNT charge free-air detonation, using four quartz free-field ICP ® blast pressure pencil probes to measure the incident overpressure [ 2 ]. Silver, from the U.S. Army Aberdeen Test Center, presents a methodology for the collection of specific blast overpressure data with pencil probes that are used to develop and analyze the effectiveness of competing cannon designs, to refine and validate Computational Fluid Dynamics models of large-caliber muzzle blasts [ 3 ].…”