基于ALE方法的弹性圆柱壳入水时的流固耦合模拟

为了获得头型及材料弹性对圆柱壳入水过程中头部变形、压力分布、入水空泡形态及入水运动状态的影响,采用ALE方法,基于有限元软件ANSYS\LS-DYNA,对平头、120°锥角、90°锥角弹性圆柱壳的入水过程进行了数值模拟,对平头弹性圆柱实体和平头刚性圆柱壳进行计算,并对模拟结果进行对比。结果表明:入水过程中空泡直径随着锥角的增大而增大,锥角越大,圆柱壳上表面的变形越大,最大变形出现的时间越早:平头弹性圆柱壳在0.1 ms时出现最大变形0.84 mm,120°锥角弹性圆柱壳在0.3 ms时出现最大变形0.54 mm,90°锥角弹性圆柱壳在0.5 ms时出现最大变形0.43 mm; 下表面受到的压力越大,圆柱壳的速度衰减越快; 平头圆柱壳下表面的变形与振动频率大于上表面; 上表面的变形是由惯性引起的,下表面的变形是由流体冲击力引起的。

Fluid-solid Interaction Simulation of Elastic Cylindrical Shell Penetrating Water Based on the ALE Method

In order to obtain the influence of the head shape and material elasticity on the deformation,pressure distribution,cavity shape and motion state of cylindrical shell in the process of water entry,Arabic Lagrange Euler(ALE)method was used to simulate and analyze the water entry process of elastic cylindrical shell with flat head,120°cone angle and 90°cone angle based on the finite element software ANSYS\LS-DYNA.The simulation result of rigid cylindrical shell was compared with that of flat head projectile.The results show that the diameter of cavity increases with the increase of the cone angle.The larger the cone angle is,the larger the deformation of the top surface of cylindrical shell is,and the earlier the maximum deformation occur.The maximum deformation of flat elastic cylindrical shell is 0.84 mm at 0.1 ms,and the maximum deformation of elastic cylindrical shell with 120°cone angle is 0.54 mm at 0.3 ms,and the maximum deformation of elastic cylindrical shell with 90°cone angle is 0.43 mm at 0.5 ms.The greater the pressure on the bottom surface,the faster the velocity of cylindrical shell decays.The deformation and vibration frequency of the bottom surface of flat head cylindrical shell is higher than that of the top surface.The deformation of the top surface is caused by inertia,and the deformation of the bottom surface is caused by the impact force of the fluid.