Strain Growth and Water Suppression in Spherical Explosion Containment Vessels Under Eccentric Blast Loading

Abstract Strain growth is a phenomenon observed in the dynamic elastic response of explosion containment vessels subjected to internal blast loading, which has not been fully clarified. In this study, the dynamic strain response characteristics of the spherical shell under eccentric loading are investigated through numerical analysis, and the mechanism of strain growth is revealed in combination with theoretical analysis. Furthermore, to evaluate the feasibility of water mitigation in suppressing strain growth, a comparative analysis of strain responses is conducted between spherical shells submerged in water and those in air under identical eccentric blast conditions. The results show that the eccentric blast loading leads to strain growth in the spherical shell, mainly due to the superposition of different membrane vibration modes. Although the increase in explosive eccentricity excites more composite modes, it does not necessarily exacerbate the strain growth. Within the elastic range, the ratio of shell thickness to radius has a limited effect on strain growth factor, while the ratio of charge radius to spherical shell (charge mass) is more critical to strain growth. The first peak strain and the maximum strain of the shells submerged in water are significantly lower compared to the shells in air. Water protection can effectively suppress or even prevent the occurrence of strain growth. These findings hold significant implications for the design and protection of explosion containment vessels.