Analysis of explosion in enclosure based on improved method of images

Abstract

The aim of this paper is to present an improved method to calculate the pressure loading on walls during a confined explosion. When an explosion occurs inside of an enclosure, reflected shock waves produce multiple pressure peaks at a given wall location, especially at the corners. The effects of confined blast loading may bring about more serious damage to the structure due to multiple shock reflection. An approach, first proposed by Chan to describe the track of shock waves based on the mirror reflecting theory, using the method of images (MOI) is proposed to simplify internal explosion loading calculations. An improved method of images is proposed that takes into account wall openings and oblique reflections that cannot be considered with the standard MOI. The approach, validated using experimental data, provides a simplified and quick approach for loading calculation of a confined explosion. The results show that the peak overpressure tends to decline as the measurement point moves away from the center, and increases sharply as it approaches the enclosure corners. The specific impulse increases from the center to the corners. The improved method is capable of predicting pressure-time history and impulse with an accuracy comparable to that of three-dimensional AUTODYN code predictions.

Study on Pressure Characteristics and Its Evolution Law at the Ellipsoidal End Cover Pole of Cylindrical Explosion Containment Vessels

“…The mapping method was used to map the calculation results of the one-dimensional explosive shock wave to the two-dimensional model, which ensured the calculation accuracy while maintaining simpler calculations [17][18][19]. The symmetrical boundaries of the two planes, both xoz and yoz, were set, respectively.…”

“…Sci. 2019, 9, x FOR PEER REVIEW 4 of 10 maintaining simpler calculations[17][18][19]. The symmetrical boundaries of the two planes, both xoz and yoz, was used to fill the explosive at the origin of the one-dimensional air grid.…”

Shock wave propagation in a double room model

“…This method assumes that the blast waves are produced by the explosive source and the images reflected from the enclosure wall. As this method cannot be used in a multi-room model, a different version of the method of images was created by Wu et al (2017) to analyse reflections in an enclosure with an opening. Another method to predict reflection is based on the shortest path algorithm from Dijkstra (1959).…”