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

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 ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:mrow> </mml:math> ), width ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> ), and height ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>h</mml:mi> </mml:mrow> </mml:math> ). 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 ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>h</mml:mi> <mml:mo>/</mml:mo> <mml:mi>l</mml:mi> </mml:mrow> </mml:math> ) while keeping <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:mrow> </mml:math> equal to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> . In the second scenario, the length-to-width ratio ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>1</mml:mn> </mml:msub> <mml:mo>/</mml:mo> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> ) was modified while maintaining a constant height ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>h</mml:mi> </mml:mrow> </mml:math> ), leading to changes in the explosive’s shape. The effects of both the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>h</mml:mi> <mml:mo>/</mml:mo> <mml:mi>l</mml:mi> </mml:mrow> </mml:math> ratio and the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>1</mml:mn> </mml:msub> <mml:mo>/</mml:mo> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>h</mml:mi> <mml:mo>/</mml:mo> <mml:mi>l</mml:mi> </mml:mrow> </mml:math> ratio increased. Furthermore, the size of the breached hole gradually diminished with an increasing <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>h</mml:mi> <mml:mo>/</mml:mo> <mml:mi>l</mml:mi> </mml:mrow> </mml:math> ratio. In terms of changes to the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>1</mml:mn> </mml:msub> <mml:mo>/</mml:mo> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>/</mml:mo> <mml:mn>4</mml:mn> <mml:mo>≤</mml:mo> <mml:mi>h</mml:mi> <mml:mo>/</mml:mo> <mml:mi>l</mml:mi> <mml:mo>≤</mml:mo> <mml:mn>4</mml:mn> </mml:mrow> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>/</mml:mo> <mml:mn>4</mml:mn> <mml:mo>≤</mml:mo> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>1</mml:mn> </mml:msub> <mml:mo>/</mml:mo> <mml:msub> <mml:mi>l</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:mo>≤</mml:mo> <mml:mn>4</mml:mn> </mml:mrow> </mml:math> ) to cubic explosives (where <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>h</mml:mi> <mml:mo>=</mml:mo>