基于可压缩流体力学基本理论，采用间断迦辽金（DG）方法结合直接虚拟流（DGF）方法和水平集（LS）方法(简称LS-DGF-DG方法)，首先建立水下爆炸爆轰模型，对不同装药形式的水下爆炸冲击波载荷进行对比研究，分析讨论装药形状对冲击波载荷特性和爆轰产物初始形态的影响，随后将数值结果与经验公式进行对比，验证LS-DGF-DG计算程序的有效性，最后通过非线性有限元软件ABAQUS建立船体加筋板架模型，将LS-DGF-DG计算得到的近场水下爆炸载荷传输给ABAQUS，模拟加筋板架结构在近场水下爆炸载荷作用下的毁伤过程，并将计算结果与实验进行对比分析，总结相关规律。结果表明：起爆初期，柱形装药逐渐形成椭球形的爆轰产物，最终膨胀为球形；装药径向的冲击波压力峰值高于轴向，柱形装药的冲击波压力峰值高于球形装药的压力峰值；在近场水下爆炸载荷的作用下，加筋板架结构出现塑性大变形和剪切破坏的现象，数值结果与试验值吻合良好；加强筋的强弱对板架结构的破坏模式和塑性变形程度有较大影响,加强筋较强，破坏首先从加强筋位置出现，加强筋较弱，破坏主要出现在固支边界处。
Based on compressive fluid dynamics, we combine Discontinuous Galerkin (abbreviated as DG) method with Level Set (abbreviated as LS) method and Direct Ghost Fluid (abbreviated as DGF) method to study load characteristics of underwater explosion. Firstly, the detonation models of underwater explosion for the charges with different shapes are established to investigate the influence on the shock wave loading and the initial shapes of the bubble. Secondly, the numerical results are compared with the experimental data to verify the validity of LS-DGF-DG method. Finally, ABAQUS is utilized to simulate the deformation of hull grillage subjected to underwater explosion, based on the results of LS-DGF-DG method. In addition, the damage characteristics of hull grillage are investigated through the comparison between the numerical and experimental results. The results show that the cylindrical charge gradually develops into ellipsoidal detonation product and eventually becomes a spherical bubble. Besides, the pressure peak in the radial direction is higher than that in the axial direction, and the pressure peak of the cylindrical charge is higher than that of spherical charge. In addition, the numerical results show good agreement with the experimental ones. It was found that hull grillage is damaged by underwater explosion along with the generation of the crevasse and plastic deformation. Besides, the stiffeners have a great influence on the damage modes of the hull grillage.
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