Interaction of Structural Member with Near Field Detonation: Effect on Shock Wave Pattern and Overpressure Profile

Abstract

During a detonation of high energetic material in Air (free air detonation), a spherical shock wave is generated with a peak overpressure corresponding to the Friedlander curve. The peak overpressure changes when the detonation of the charge is carried under the Soil (e.g. land mine detonation). The differences in peak overpressure and the distribution pattern are observed on considering both the detonation conditions (buried under the Soil and free Air). The changes are more significant in the case of the near field scenario (scaled distance < 0.2 m/kg^1/3) when compared to the far-field scenario (scaled distance > 0.2 m/kg^1/3). The shock wave pressure distribution in the near field gets further affected when the target objects (a structural member, a person, or both) are interacting with the detonation. The structural member could be a part of a protective equipment or a standard equipment. When interacting with the detonation, the structural member or person changes the shock wave pattern and alters the overpressure experienced by one another. Also, based on the shape and size of the structural member, the value of overpressure and pattern exposed to the person could be different. The current numerical study summarises the effect of introducing a structural member in a near field scenario when the detonation of a charge is carried out under the Soil. The study is performed using a simulation technique called MM-ALE (multi-material arbitrary Lagrangian Eulerian) available in commercially available software, LS-Dyna. A numerical simulation has been performed for a detonation event by introducing different structural members in the near field. Variation of peak overpressure in the close range has been studied. It has been found that the predicted pattern of the overpressure agrees with the Friedlander curve.