Experimental and numerical research on multi-model structural damage under shockwave-projectile-bubble action

Abstract

The underwater explosion (UNDEX) of a shaped charge is a continuous physical process. However, the interaction between the shockwave, the shaped charge projectile, and the bubble interacting with the structure involves multi-scale temporal and spatial challenges. First, this research conducted damage experiments on a hemispherical double-hull structure influenced by the UNDEX of a shaped charge. The experiment recorded the shockwave load, bubble load, and structural response, capturing the bubble's radius, period, shape, and secondary pulsation. Secondly, the Coupled Eulerian-Lagrangian (CEL) method was employed to simulate the UNDEX experiments. This approach addressed the shortcomings of incomplete field output in the experimental method. It addressed the multi-scale temporal and spatial challenges involved in the interaction between the shockwave, the shaped charge projectile, and the bubble interacting with the structure. It revealed the temporal and spatial evolution laws of the shockwave, shaped charge projectile, and bubble load. The research provided insights into the bubble dynamics near the elastic-plastic structure during UNDEX. The combined effects of the shockwave, shaped charge projectile, and bubble load resulted in a distinct structural damage model. Furthermore, the shaped charge UNDEX consists of four phases: shockwave projectile, bubble expansion, bubble contraction, and bubble pulsation. Lastly, the CEL method analyzed the contributions of the inner and outer hull responses and deformations during the four phases. Additionally, the research established the relationship between the distance parameter γ and the structural damage model. The results show that when γ < 1.83, shear failure occurs in the outer hull, no failure occurs otherwise. When γ < 0.43, shear failure occurs in the inner hull, no failure occurs otherwise. Between γ = 0.0 and 2.0, the bubble pulsation phase contributes about 80 % to the structure deformation D of the outer hull and 60 % to the inner hull. For shaped charge contact or near-field explosions, consider the combined effects of the three loads on multi-model structural damage, especially the long-duration bubble load. This research used experimental and the CEL methods to address the multi-scale temporal and spatial issues in the interaction of the shockwave, shaped charge projectile, and bubble with the structure. The purpose of this research is to provide a reference for addressing the multi-scale temporal and spatial issues in the interaction of the shockwave, shaped charge projectile, and bubble with the structure.