基于SPH-FEM方法的水下近场爆炸数值模拟研究

Numerical investigation on near-field underwater explosion using SPH-FEM method

针对结构水下近场爆炸载荷作用响应求解难点,通过改进的三维轴对称光滑粒子流体动力学方法(Smoothed Particle Hydrodynamics,SPH)计算获得近场爆炸载荷后传输给非线性有限元软件ABAQUS,利用声固耦合模型对结构响应进行时域非线性计算,形成预报水下近场爆炸载荷对结构毁伤的SPH-FEM模型,实现从药包起爆、结构大幅变形、局部撕裂直至完全剪切破坏的全过程模拟,对载荷时历曲线进行试验验证。计算背空矩形钢板在近场爆炸载荷的响应表明,数值结果与试验值吻合良好。SPH-FEM模型计算效率高、可操作性强,易推广至大型复杂结构受水下近场爆炸毁伤的分析与评估。

The response of structures subjected to underwater shock wave is a highly nonlinear problem, the main difficulties of which are in the determination of the magnitude of shock wave load and the response of structures under transient load. Based on an improved axisymmetric Smoothed Particle Hydrodynamics （SPH） method, the near-field load of the underwater explosion was calculated and then it was used as the input to the FEM package ABAQUS. By using a coupled acoustic-structure model in ABAQUS, the nonlinear response of the structure was obtained. Based on the SPH- FEM model, the whole process of the near-field underwater explosion was simulated, starting from the detonation of the explosive charge to the large deformation, local tearing and complete damaging of the structure. The theoretical explanation of the axisymmetric SPH method was presented in detail and the calculated shock wave pressure load was validated by the experimental data. Then, the responses of rectangular plates subjected to near-field explosion were numerically investigated. The numerical results agree well with the experimental observations. Some useful conclusions regarding near-field explosion were drawn. The SPH-FEM model introduced here is robust and efficient, which is suitable for engineering applications.