轴-艇耦合系统自由振动特性建模与分析  

Modeling and analysis of the free vibration characteristics of the shaft-hull coupling system

作　　者：聂睿 李天匀[1,2,3] 朱翔 陈旭[1,3] NIE Rui;LI Tianyun;ZHU Xiang;CHEN Xu(School of Naval Architecture and Ocean Engineering,Huazhong University of Science&Technology,Wuhan 430074,China;Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration,Shanghai 200240,China;Hubei Key Laboratory of Naval Architecture&Ocean Engineering Hydrodynamics,Wuhan 430074,China)

机构地区：[1]华中科技大学船舶与海洋工程学院,湖北武汉430074 [2]高新船舶与深海开发装备协同创新中心,上海200240 [3]船舶与海洋水动力湖北省重点实验室,湖北武汉430074

出　　处：《哈尔滨工程大学学报》2023年第6期953-961,共9页Journal of Harbin Engineering University

基　　金：国家自然科学基金项目(51839005,51879113);中央高校基金科研业务费资助项目(2019kfyMBZ048)。

摘　　要：为了探究水下航行器结构间的振动传递规律,本文基于能量变分原理,以梁-组合壳作为轴-艇耦合系统结构的简化,建立理论计算模型并对其自由振动特性进行分析。引入改进傅里叶级数构造梁结构及组合壳结构的位移函数,得到各自结构的动能和应变能;分别利用耦合弹簧组和边界弹簧组将结构之间的位移连续条件和边界约束条件转换为对应的耦合弹簧势能;对系统能量泛函进行变分求解,得到耦合系统的固有频率及模态振型。通过与有限元软件的对比,验证了本文计算模型的准确性,并对不同壳体边界条件下耦合系统固有频率变化规律进行计算分析。研究结果表明:耦合系统低频段存在解耦模式,振动模态可等效于刚体结构上的多跨梁弯曲振动;壳体边界约束增强会导致耦合系统大部分固有频率随之增大并最终趋于稳定,但不会对解耦模式的固有频率产生影响。On the basis of the energy variation principle,a theoretical calculation model is established using a beam-combined shell as the simplification of the shaft-hull coupling system structure to analyze its free vibration characteristics and explore the vibration transfer law between underwater vehicle structures.First,the displacement functions of the beam structure and composite shell structure constructed by improved Fourier series are introduced to obtain the kinetic and strain energies of their respective structures.Displacement continuity condition and boundary constraint between structures are then converted into corresponding coupling spring potential energy using the coupling and boundary spring groups,respectively.Finally,the energy functional of the system is solved using a variational method to obtain the natural frequency and mode shape of the coupled system.The accuracy of the calculation model is verified through comparison with finite element method(FEM)software,and the natural frequency variation law of the coupling system under different shell boundary conditions is calculated and analyzed.The results show a decoupling mode in the low-frequency band of the coupling system.The vibration mode is equivalent to the bending vibration of a multispan beam on the rigid body structure.Enhanced shell boundary constraints prompt most of the natural frequencies of the coupled system to rise correspondingly and eventually stabilize but do not affect the natural frequencies of the decoupling mode.

关 键 词：水下航行器 轴-艇耦合系统 自由振动特性 能量变分原理 改进傅里叶级数 固有频率 模态振型 边界约束 

分 类 号：O327[理学—一般力学与力学基础]