This paper presents a novel approach for analyzing the effects of near-field underwater blast loading on composite marine structures. The operational requirements of these structures often expose them to blast or shock loading, which can lead to significant damage. The study focuses on the propagation of spherical blast waves and the subsequent secondary bubble collapse pulse that affects the structure under near-field underwater blast loading events. An analytical framework is developed to calculate the blast energies and structural energies during this complex loading event. The study further investigates the effect of applying a sacrificial cladding made of low-density closed-cell foam to the loading face of a composite panel. Experiments were conducted in a specialized facility to characterize the explosive-driven blast-loading and the subsequent interaction between the shock pressure front and the structure. Dynamic pressure measurements and high-speed imaging were utilized to capture the behavior of the composite panel under these extreme conditions. 3D digital image correlation was employed to analyze strain and deformation of the composite panel, while high-speed side view cameras captured the fluid-structure interaction during the blast and bubble collapse loading event. The results strongly indicate that the collapse of the explosion bubble is the dominant failure source in near-field underwater blast loadings. The analytical quantification of energy further corroborates the significant damaging effects of bubble collapse due to the buildup of after-flow energies during the bubble collapse duration. Furthermore, the inclusion of low-impedance elastic-plastic PVC foam cladding is shown to significantly mitigate the effect of blast loading on the composite structure.

中文翻译：

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PVC泡沫复合板水下炸药装载能量量化框架

本文提出了一种分析近场水下爆炸载荷对复合海洋结构影响的新方法。这些结构的操作要求经常使它们承受爆炸或冲击载荷，这可能导致严重损坏。该研究的重点是球形爆炸波的传播以及随后在近场水下爆炸载荷事件下影响结构的二次气泡破裂脉冲。开发了一个分析框架来计算这一复杂加载事件期间的爆炸能量和结构能量。该研究进一步研究了将低密度闭孔泡沫制成的牺牲覆层应用于复合板的承载面的效果。在专门的设施中进行了实验，以表征爆炸驱动的爆炸载荷以及随后冲击压力前沿与结构之间的相互作用。利用动态压力测量和高速成像来捕获复合板在这些极端条件下的行为。采用 3D 数字图像相关分析复合材料板的应变和变形，同时高速侧视摄像机捕获爆炸和气泡破裂加载事件期间的流体-结构相互作用。结果强烈表明，爆炸气泡的破裂是近场水下爆炸载荷中的主要破坏源。能量的分析量化进一步证实了由于气泡破裂持续期间后流能量的积累而导致的气泡破裂的显着破坏作用。此外，低阻抗弹塑性 PVC 泡沫覆层的加入可以显着减轻爆炸载荷对复合结构的影响。