The effect of cuboid explosive shape on the dimension of damaged area in masonry walls subjected to contact explosions

Abstract

Cuboid explosives are commonly available in both military and civilian markets. Masonry walls are among the most prevalent structural elements utilized in buildings worldwide. This study numerically investigates the response of masonry walls subjected to blast loads generated by cuboid explosives. The LS-DYNA software was employed to create numerical models, which were subsequently validated against experimental data. The shape of the cuboid explosives is characterized by its three-dimensional dimensions: length ( $l_{1}$ ), width ( $l_{2}$ ), and height ( $h$ ). To maintain a constant mass of explosives, two distinct scenarios were considered. In the first scenario, the explosive’s shape was altered by adjusting the height-to-length ratio ( $h / l$ ) while keeping $l_{1}$ equal to $l_{2}$ . In the second scenario, the length-to-width ratio ( $l_{1} / l_{2}$ ) was modified while maintaining a constant height ( $h$ ), leading to changes in the explosive’s shape. The effects of both the $h / l$ ratio and the $l_{1} / l_{2}$ ratio on the dynamic responses of the masonry walls were investigated. The results indicate that the dimensions of both the ejection crater and the spalling crater on the masonry wall initially increased and then decreased as the $h / l$ ratio increased. Furthermore, the size of the breached hole gradually diminished with an increasing $h / l$ ratio. In terms of changes to the $l_{1} / l_{2}$ ratio, the damage area of the masonry wall took on an elliptical shape, with the dimensions of this elliptical damage area exhibiting regular variations. This study aimed to equate cuboid explosives (with $1 / 4 \leq h / l \leq 4$ and $1 / 4 \leq l_{1} / l_{2} \leq 4$ ) to cubic explosives (where $h = l_{1} = l_{2}$ ) of the same mass. The equivalent cubic shape coefficients ( $η$ ) for the cuboid explosives were evaluated and calculated based on the dimensions of the damage area on the masonry wall. Furthermore, four coefficients ( $η_{1}$ to $η_{4}$ ) were proposed to estimate the dimensions of the masonry wall damage area when subjected to contact explosions from arbitrarily shaped cuboid explosives. The applicability of these coefficients was validated through numerical simulations.

Keywords

Cuboid explosives shape equivalent cubic shape coefficients full scale tests explosive masonry walls

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