水下爆炸气泡与复杂弹塑性结构的相互作用研究

计及结构的弹塑性，将边界元法(BEM)与有限元法(FEM)耦合提出了气泡与弹塑性结构耦合动力学计算方法，并开发了全套的三维水下气泡分析程序（UBA），计算值与实验值之间误差在10%以内．以水面舰船为例，将三维计算程序工程化．并分析了水下爆炸气泡载荷作用下船体的弹塑性响应，从船体结构典型单元上的应力时历曲线可以看出，在气泡坍塌时出现应力峰值，证实了气泡坍塌压力及射流引起的压力对舰船等结构造成严重毁伤．从气泡与舰船的相互作用中可以看出，舰船低阶垂向振型被激起，在气泡作用下呈鞭状运动，同时舰船随着气泡的膨胀和收缩作升沉运动，通过本文的分析得到了适合于工程应用的规律及结论．

Interaction of Underwater Explosion Bubble With Complex Elastic-Plastic Structure

Considering structure of elastic-plasticity, the combination of boundary element method and finite element method (FEM) was employed to present the calculation method for solving the complex coupling dynamic problem of bubble, plastic-elastic structure and free surface, and the complete threedimensional calculation program was developed as well. The error between calculated result yielded by the program and experimental result is within 10%. Taking surface ship as an example, the three-dimensional calculation program was converted in order to conveniently settle complex elastic-plastic structure problem in engineering field. Finally, a full system of coupling dynamic analysis program was completed, which is fit for solving interaction of three-dimensional bubble with elasticplastic structure in engineering application, aiming at present preference for further research on dynamics of bubble induced by ship underwater explosion. By employing the program, the response of ship under the bubble loading is analyzed. From the wall pressure-time history and stress-time history curves of typical elements of structure, it can be seen that the pressure reaches maximum when the bubble collapses and this validates that the pressure generated by the collapsing of bubble and the jet causes serious damage to the ship structure. From the dynamic process of the interaction of the threedimensional bubble and ship, the low order mode of the ship is provoked and the ship presents whipshaped motion. And the ship does elevation and subsidence movement with the expansion and shrinkage motion of the bubble.