冲击波和气泡作用下舰船结构动态响应的数值模拟

Numerical simulation of dynamic response of warship structures subjected to underwater explosion shockwaves and bubbles

针对水下爆炸载荷、瞬态流固耦合效应在舰船水下爆炸数值模拟中的困难,在现有水下爆炸载荷计算模型(Geers and Hunter)的基础上,结合边界元法,修正水下爆炸气泡载荷计算方法。针对用二阶双渐近法(the second-order doubly-asymptotic approximation,DAA2)在处理低频大幅运动流固耦合问题时的局限性,提出非线性双渐近法(nonlinear doubly-asymptotic approximation,NDAA),计入了舰船大幅低频运动、自由面效应等非线性因素,并与结构有限元程序相结合,形成一套适合于工程应用研究的舰船水下爆炸数值模拟程序。数值模拟结果与实验结果的平均误差在16.8%左右,说明NDAA方法可为冲击波和气泡对舰船结构毁伤数值模拟提供参考。

Aimed at the difficulties of underwater explosion load and instantaneous fluid-structure interaction in the numerical simulation of dynamic response of warship structures,based on the Geers-Hunter model,a modified model for calculating the underwater explosion bubble load was proposed by combining with the boundary element method.To overcome the shortcoming of the second-order doubly-asymptotic approximation（DAA2） method in treating the fluid-structure interaction with low frequency and large amplitude motion,a nonlinear double asymptotic approximation（NDAA） method was presented by considering the nonlinear factors such as the violent low-frequency response of the warship and its free surface effect.And a code was developed by combining the presented NDAA method with the finite element code to numerically investigate the dynamic response of warship structures subjected to underwater explosion shockwaves and bubbles.The mean error between numerical and experimental vertical vibration velocities at the different positions is about 16.8%,and it displays that the presented NDAA method is feasible.