浅水爆炸荷载特性的数值拟合

Numerical fitting of load characteristics of shallow water explosion

浅水爆炸涉及复杂的边界条件,其荷载特性与自由场水下爆炸有明显不同。基于LS-DYNA有限元软件通过建立浅水爆炸数值计算模型,依据已有经验公式验证数值方法的有效性,分析了水面和水底对冲击波荷载特性的影响,对比软泥水底和岩石水底对冲击波传播的影响,建立浅水爆炸峰值荷载、比冲量拟合公式。研究表明:浅水爆炸峰值压力由炸药深度向水面、水底两端衰减,比冲量由水底至水面衰减;在距离近水面、水底区域,冲击波受水面切断效应和水底叠加效应影响显著。引入边界距离为影响因子,基于经典经验公式和数值仿真结果建立浅水爆炸峰值荷载和比冲量的拟合公式,并通过浅水爆炸试验验证拟合公式的适用性。

Shallow water explosion involves complex boundary conditions,and its load characteristics are obviously different from those of free-field underwater explosion.The numerical calculation model of shallow water explosion is established based on the LS-DYNA finite element software,and the existing empirical formula verify the validity of the numerical method.The influence of water surface and bottom on the load characteristics of shock wave is analyzed.By comparing the influence of soft mud bottom and rock bottom on shock wave propagation,the fitting formula of peak load and specific impulse of shallow water explosion is established.The results show that the peak pressure of shallow water explosion decays from the depth of the explosive to both ends of water surface and bottom,and the specific impulse decays from water bottom to surface.In the area close to water surface and bottom,the shock wave is significantly affected by the water surface cut-off effect and the underwater superposition effect.Based on the classical empirical formula and numerical simulation results,the fitting formula of peak load and specific impulse of shallow water explosion is established by introducing the boundary distance as the influence factor,and the applicability of the fitting formula is verified by shallow water explosion test.