Numerical study of structural damage mechanization exposed to LPG explosion in limited space

Liquefied petroleum gas (LPG) is widely used for restaurant fuel while it may cause severe explosion due to its flammable and explosive properties such as the "6·21" explosion in China in 2023 (31 deaths and 7 injuries). Many studies have been conducted to analyze and predict LPG explosion overpressure while limited attempts the structure damage mechanization which is essential for assessing secondary damage. This paper analyzes the structural damage mechanization caused by LPG explosion in limited space using a Finite element method (FEM). In the FEM model, Arbitrary Lagrangian-Eulerian (ALE) algorithm is utilized to model the fluid-structure interaction and thus obtain the dynamic response of building structure exposed to LPG explosion. The dynamic response of building structure is analyzed in the change of effective plastic strain, velocity, displacement, and kinetic energy absorbed by the wall. The structural failure process of walls and doors is analyzed, considering sizes of door, numbers of door, placement of door, and the mass of LPG involved in the explosion. Accordingly, the evolution of structural damage caused by LPG explosions in limited space can be obtained. The results show that the dynamic response of structures in the explosion closely depends on the sizes of door, numbers of door, placement of door, and LPG mass. Besides, the structure with obstacles (Wall) can effectively resist the diffusion of explosion waves and decrease peak overpressure, which is 52.08 %. Moreover, the displacement of the door frame always gradually increases from the bottom to the top, independent of the size of the door. The research method in this paper offer ideas for the blast-resistant evaluation, design and retrofitting of building structure.