动水中带封板圆柱壳振动的轴对称有限元⁃边界元耦合计算方法  

Vibration analysis of cylindrical shells with endplates in axial flow:an axisymmetric FEM⁃BEM method

作　　者：张德春 陈浩然[1] 李鹏[1] 刘桂祥[2] 杨翊仁[1] ZHANG Dechun;CHEN Haoran;LI Peng;LIU Guixiang;YANG Yiren(School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu 611756,China;Nuclear Power Institute of China,Chengdu 610213,China)

机构地区：[1]西南交通大学力学与航空航天学院,四川成都611756 [2]中国核动力研究设计院,四川成都610213

出　　处：《振动工程学报》2025年第4期687-696,共10页Journal of Vibration Engineering

基　　金：国家自然科学基金资助项目(12072298)。

摘　　要：针对水环境中带封板圆柱壳的动力学计算提出了一种轴对称有限元⁃边界元耦合计算方法。基于结构的周期性特征,圆柱壳和封板的运动可通过其母线的运动唯一确定。将母线离散为若干个单元以进行有限元求解。通过能量法获得单元矩阵并组装成总体矩阵,建立了结构运动的有限元计算格式;考虑流体的轴对称特征,在结构母线上建立轴对称边界元并构建了流弹压力的边界元计算格式;获得流体压力后将其转换为有限元节点的等效节点力,其表现为流体附加质量、阻尼和刚度;结合结构运动方程和流弹压力计算格式,构造了求解该类流⁃固耦合问题的轴对称有限元⁃边界元耦合计算方法。本文计算结果与已有理论解和商用分析软件计算结果吻合较好,表明了本文方法的准确性。相比于商用分析软件,本文方法具有更高的计算效率,可直接获得圆柱壳在流体中的质量和刚度矩阵,有利于受迫振动的快速计算。基于本文方法分析了端部含封板复杂圆柱壳在动水中的湿频率和稳定性特性,结果表明:封板会改变壳体表面流动特性,更易诱发圆柱壳的流弹失稳。An axisymmetric finite element-boundary element coupled computational method is proposed for the dynamics of cylindrical shells with endplates in water.Due to the periodic characteristics of the structure,the movement of the cylindrical shell and end plate can be determined by examining their meridional movement,and the meridians are discretized into several elements for further analysis.By using the energy method,the elemental matrices are obtained and assembled into the global matrices.Then the discrete schemes for structural motion with the finite element is established.Considering the axisymmetric characteristic of the fluid,an axisymmetric boundary element on the meridians is established and the calculation format for fluid-elastic forces on the finite elements is given.The fluid forces are then converted into an equivalent nodal force at the nodes and the effects of the fluid are evaluated by the added mass,damping,and stiffness matrices.By combining the structural motion and the schemes of fluid-elastic forces,an axisymmetric finite element-boundary element coupling method is developed to solve this fluid-structure coupling problem.The calculated results presented in this paper demonstrate good agreement with existing theoretical solutions and commercial analysis software,validating the accuracy of present method.Moreover,this method exhibits higher computational efficiency compared to commercial analysis software.It allows for direct determination of the mass and stiffness matrices of cylindrical shells in fluid,facilitating fast calculation of forced vibration.Based on this method,the wet frequencies and stability characteristics of complex cylindrical shells with end plates in axial flow are analyzed.The results show that the end plates will change the flow velocities on the cylindrical shell and make it more easily to instability.

关 键 词：圆柱壳 流⁃固耦合 封板 轴向流 有限元⁃边界元耦合 

分 类 号：O327[理学—一般力学与力学基础]