中空细长圆柱壳内爆机理及其诱导链式失效研究

Numerical study on the implosion of hollow slender cylindrical shells and the induced chain failure

本文采用耦合欧拉-拉格朗日(CEL)方法模拟深海中空细长圆柱壳在外压作用下的内爆。通过试验数据对数值计算结果进行校准,得到内爆过程中壳体和周围流体的响应,揭示多个壳体并排布置时的流固耦合机理。计算结果表明:圆柱壳内爆是一个瞬态高能动力事件,在内爆过程中,周围的流体高速涌向壳体,导致压力分布发生空间变化,进而导致相邻壳体发生预变形,这种变形增加了壳体失稳的可能性;此外,内爆壳体内表面一旦发生接触,就会导致高速流动流体撞击壳体外表面,流体动量的瞬时变化会产生向外辐射的脉冲波,且压力脉冲峰值远高于环境压力,这将使邻近壳体进一步发生变形,从而诱发链式内爆反应。

In this paper,the coupled Eulerian-Lagrange(CEL)method was used to simulate the implosion of a deep-sea hollow slender cylinder shell under external pressure.The numerical results were validated by test data,and then the response of the shell and the surrounding fluid during implosion were obtained.The fluid-structure interaction(FSI)mechanism with multiple shells arranged side by side was also revealed.The results show that the implosion of a cylindrical shell is a transient high-energy dynamic event.During the implosion process,the surrounding fluid rushes toward the shell at high speed,which results in spatially-varying pressure distribution and a pre-deformation of the adjacent shell.And such pre-deformation increases the possibility of shell buckling.Besides,the rushing fluid impacts the external surface of the shell once the inner surface of the shell wall comes into contact,and an outward radiation pulse wave is generated due to the instantaneous change of fluid momentum,the peak value of pressure pulse is much higher than the ambient pressure,which will deform the adjacent shells further and induce the chain implosion reaction.