中心内爆引起的圆柱壳流固耦合问题数值模拟

针对中心装药的冲击波加载,研究了椭球封头圆柱壳的流固耦合问题.基于法向位移、速度和力建立流固界面边界条件,采用FVM求解积分ALE型无粘流体力学方程组,采用FEM求解虚功原理,得到内爆流场冲击波和壳体应力波的传播过程.结果表明:我们的方法和计算软件可研究内爆引起的壳体流固耦合问题.尽管壳体结构和装药位置相对简单,但冲击波在壳内传播和内壁面多次反射产生的波系结构相当复杂,压力云图刻画了冲击波演化图像.壳体所受加载特征是:前期表现为冲击波超压,后期表现为冲量,壳体变形依赖冲击波加载历史.封头顶点、封头和侧壁交线以及距中心最近的中环面出现较大等效应力,也是结构易破坏的部位.

Numerical simulation on flow-structure interaction loaded by a blast wave from a central charge

In a cylindrical shell,the fluid-structure interaction induced by a centrally charged blast wave was numerically studied.The displacement,force and velocity were continuous in normal vector and imposed as the boundary conditions between the fluid and shell.FVM was used to discretize the integrated ALE inviscid equations,and FEM was adopted to discretize the virtual work principle in Lagrangian frame.The algorithm and computational code were well developed for the numerical analysis of the flow-structure shocked by blast waves.In the case of a cylinder with simple geometry and a central charge,the blast waves were very complex coupled with propagation and reflection,transmission processes inside the chamber.The detailed wave structure and the pressure history curve at specified points depended on the charge amount and location,cylinder aspect ratio.The loading at each point along the shell inner surface was determined by overpressure initially and impulse latterly.The shell deformation depended on the loading history.The maximum equivalent stresses appeared at the top and median line of the ellipsoid cover,as well as the line between the cover and the side-wall.The structure was easily damaged at these locations.