有限元法的轴向运动梁的激励功率谱辨识  

IDENTIFICATION OF EXCITATION POWER SPECTRUM DENSITY FOR AN AXIALLY MOVING BEAM USING FINITE ELEMENT METHOD

作　　者：刘涛[1] 罗梦翔 吴炜[2] 史济涛[2] 蔡国平[1] 

机构地区：[1]上海交通大学工程力学系,海洋工程国家重点实验室,上海200240 [2]中国空空导弹研究院,洛阳471009

出　　处：《动力学与控制学报》2016年第2期186-192,共7页Journal of Dynamics and Control

基　　金：国家自然科学基金资助项目(11132001,11272202);航空科学基金(20120157002);上海市教委科研重点项目(14ZZ021)资助~~

摘　　要：主要考虑弯曲变形的细长轴向运动梁,可以作为工程中广泛应用在航天器天线、液体输送管道、汽车驱动带、电梯缆索等的简化机构.对轴向运动柔性梁线性微分方程,采用复模态分析方法导出两端简支和固支边界条件下的固有频率方程;采用Ritz法建立轴向运动梁的有限单元法模型.基于该模型在多种边界条件下进行梁的横向振动分析,并开展定点激励下激励功率谱的辨识.仿真结果表明,与传统的Galerkin截断方法相比.有限元方法能够克服分析方法的建模困难,对复杂边界梁进行有效的分析,对激励的功率谱能够有效地辨识.Many mechanical devices,such as spacecraft antennas,pipes conveying fluid and elevator cable,can be simplified as axially moving slender beams,since their main elastic deformation is taken as transverse bending. Based on the complex model analysis procedure,the formula of natural frequency for the simple- supported and fixed beams are firstly derived from the linear differential equations in this paper. Moreover,in terms of Ritz method,a finite element model of axially moving beams is constructed. The system response under external excitation and the transforming relationship of power spectrum density（ PSD） between external excitation and system response in frequency domain are obtained. To this end,the PSD of external excitation through the transforming relationship is finally indentified. Importantly,it is shown from the comparison between the proposed FE model and the traditional Galerkin truncation method that the finite element method can solve the modeling problem of the analysis method,and it is more effective in identifying the PSD of external excitation for the axially moving beams with complex boundaries.

关 键 词：轴向运动梁 复模态 有限元 复杂边界 功率谱辨识 

分 类 号：TB115[理学—数学]