金属薄壳结构膨胀抛弹过程流固强耦合分析  

Fully coupled method for analyzing fluid-structure interaction in metal shell inflating to disperse bombs

作　　者：张成[1] 宁惠君[2] 江坤[1] 王浩[1] 袁倩 

机构地区：[1]南京理工大学能源与动力工程学院,南京210094 [2]河南科技大学土木工程学院,洛阳471023

出　　处：《应用力学学报》2015年第6期889-894 1095,1095,共7页Chinese Journal of Applied Mechanics

摘　　要：针对子母弹金属薄壳结构膨胀抛弹过程中流固耦合作用的特点,引入了一种计算粘性可压缩流体与经历大变形金属薄壳之间相互作用的流固强耦合方法。该方法中结构模型和流体模型分别采用Lagrange和ALE描述,二者的有限元离散方法分别为Galerkin法和基于Petrov-Galerkin变分方法的FCBI单元法。本文采用该强耦合方法对含有接触条件的金属薄壳结构膨胀抛弹的过程进行了数值仿真,所得解的收敛性良好。计算结果显示:薄壳内流场经历了定容充气、扩张充气、充气后期三个阶段;定容充气至充气后期的前半段期间(0~3ms),波谷处应力呈缓慢上升趋势,而波峰和连接段处应力在经历了1ms的周期性振荡后,分别表现为直线增大和基本不变的趋势,3ms后薄壳各处应力均快速增大。同时仿真获得的薄壳内平均压力及子弹的最大抛速与已有文献中内弹道模型结果基本一致,分别相差3.6%和5%,表明本文模型能够较为全面合理地描述金属薄壳结构膨胀抛弹的过程。According to the characteristics of fluid-structure interaction(FSI) in the process of metal shell inflating to disperse bombs, a fully coupled method for calculating a viscous compressible flow and a nonlinear structure undergoing large deformations is introduced. In this method, structure model is described by Lagrangian formulation, whereas fluid model is described by ALE formulation, and the finite element discrete format of the two models are Galerkin method and FCBI method which is based on Petrov-Galerkin variational method, respectively. The objective of this paper is to employ this fully coupled method to simulate the process of a metal shell inflating to disperse bombs within contact conditions. Results obtained show that the convergence is good and the flow field in the metal shell experiences three stages, namely, the stages of inflating with constant volume, inflating with expending volume and late inflation. During the period from 0 to 3.0ms, the stress of the whole structure increases slowly, except that at the crest of metal shell, then after 3.0ms, the stress at all points of the metal shell rapidly raises. Meanwhile, the average internal pressure and the maximum dispersing speed acquired from the FSI model are consistent to that of interior ballistic model, the differences is 3.6% and 5%, respectively. So this FSI model can accurately describe the process of a metal shell inflating to disperse bombs.

关 键 词：流固强耦合 金属薄壳 大变形 FCBI单元算法 

分 类 号：O353.4[理学—流体力学]