一种用于天线模态测试的竖向低频悬吊系统
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- 英文论文题名：A vertical low frequency suspension system used for modal testing of the large antenna
- 论文作者：葛东明 ; 郑宜生 ; 张希农
- 英文论文作者：Ge Dongming ; Zheng Yisheng ; Zhang Xinong ; Beijing Institute of Spacecraft System Engineering ; State Key Laboratory for Strength and Vibration of Mechanical Structures ; School of Aerospace ; Xi'an Jiaotong University
- 年：2016
- 作者机构：北京空间飞行器总体设计部;西安交通大学航天航空学院机械结构强度与振动国家重点实验室;
- 论文关键词：负刚度 ; 低频 ; 悬吊系统 ; 点头模态 ; 大型天线
- 英文论文关键词：negative stiffness ; low frequency ; suspension system ; nodding mode ; large antenna
- 会议召开时间：2016-08-12
- 会议录名称：第十六届全国模态分析与试验学术会议论文集
- 语种：中文
- 分类号：TN820
- 学会代码：ZGZH
- 会议名称：第十六届全国模态分析与试验学术会议
- 会议地点：中国天津
- 主办单位：中国振动工程学会模态分析与试验专业委员会
- 学会名称：中国振动工程学会
- 页数：6
- 文件大小：698k
- 原文格式：D
- 会议级别：全国
摘要
在对大型天线的点头模态频率进行测试时,由于传统的天线悬吊系统在竖直方向会对天线带来过大的附加约束,因此很难测出正确的模态频率。针对这个问题,本文提出了一种基于准零刚度原理的竖向低频悬吊系统。该悬吊系统具有很低的竖向共振频率,因此可以降低对天线点头模态频率测试的影响。该悬吊系统主要由机械弹簧和和磁力弹簧组成,磁力弹簧可以产生负刚度抵消机械弹簧的正刚度,从而降低共振频率。本文首先提出该悬吊系统模型,并计算得到其磁力、磁刚度特性。然后建立该悬吊系统的动力学模型。最后对该悬吊系统的性能进行有限元仿真研究:建立由7个悬吊装置和一口径5m的大型天线组成的有限元模型,计算在采用普通悬吊装置和本文所提出的低频悬吊装置两种工况下天线的点头模态频率。结果表明采用本文所提出的竖向低频悬吊装置时,天线的点头模态频率更接近于无悬吊装置下的真实值。
When testing the "nodding mode" frequency of a large antenna,the additional constraint can be applied to the antenna in the vertical direction if the conventional suspension system is employed,and hence the correct modal frequency could not be measured. In this paper,a suspension system based on the principle of quasi-zero stiffness is designed to solve this problem. The resonance frequency of the proposed suspension system in the vertical direction is so low that its influence on the "nodding mode" frequency is weak. The suspension system consists of a coil spring and a magnetic spring. The magnetic spring could produce negative stiffness to cancel the positive stiffness of the coil spring and hence reduce the resonance frequency. Firstly,the model of the suspension system is presented and the magnetic force and stiffness is obtained. Then the dynamic equation of the suspension system is established. Finally,the FE method is employed to verity the effectiveness of the suspension system: the FE model of a large antenna with seven suspension devices is established; then the "nodding mode" frequency of the antenna is calculated in the cases of being suspended by the conventional suspension system and by the proposed low frequency suspension system. The results show that,compared with the case of employing the conventional suspension system,the "nodding mode" frequency achieved when the proposed low frequency suspension system is employed is closer to the true value.
When testing the "nodding mode" frequency of a large antenna,the additional constraint can be applied to the antenna in the vertical direction if the conventional suspension system is employed,and hence the correct modal frequency could not be measured. In this paper,a suspension system based on the principle of quasi-zero stiffness is designed to solve this problem. The resonance frequency of the proposed suspension system in the vertical direction is so low that its influence on the "nodding mode" frequency is weak. The suspension system consists of a coil spring and a magnetic spring. The magnetic spring could produce negative stiffness to cancel the positive stiffness of the coil spring and hence reduce the resonance frequency. Firstly,the model of the suspension system is presented and the magnetic force and stiffness is obtained. Then the dynamic equation of the suspension system is established. Finally,the FE method is employed to verity the effectiveness of the suspension system: the FE model of a large antenna with seven suspension devices is established; then the "nodding mode" frequency of the antenna is calculated in the cases of being suspended by the conventional suspension system and by the proposed low frequency suspension system. The results show that,compared with the case of employing the conventional suspension system,the "nodding mode" frequency achieved when the proposed low frequency suspension system is employed is closer to the true value.
引文
[1]路波.零重力环境模拟气动悬挂系统的关键技术研究[D].浙江大学机械工程学系浙江大学,2009.
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[4]Carrella A,Brennan M J,Waters T P.Static analysis of a passive vibration isolator with quasi-zero-stiffness characteristic[J].Journal of Sound&Vibration,2007,301(3-5):678-689.
[5]Xu D,Zhang Y,Zhou J,et al.On the analytical and experimental assessment of the performance of a quasi-zero-stiffness isolator[J].Journal of Vibration&Control,2014,20(15):2314-2325.
[6]刘兴天,张志谊,华宏星.新型低频隔振器的特性研究[J].振动与冲击,2012,31(5):161-164.
[7]Zheng Y,Zhang X,Luo Y,et al.Design and experiment of a high-static-low-dynamic stiffness isolator using a negative stiffness magnetic spring[J].Journal of Sound&Vibration,2016,360:31-52.
[2]Woodard S E,Housner J M.The nonlinear behavior of a passive zero-spring-rate suspension system[J].Journal of Guidance Control&Dynamics,1988,14(1):84-89.
[3]White G,Xu Y.An active vertical-direction gravity compensation system[J].Instrumentation&Measurement IEEE Transactions on,1994,43(6):786-792.
[4]Carrella A,Brennan M J,Waters T P.Static analysis of a passive vibration isolator with quasi-zero-stiffness characteristic[J].Journal of Sound&Vibration,2007,301(3-5):678-689.
[5]Xu D,Zhang Y,Zhou J,et al.On the analytical and experimental assessment of the performance of a quasi-zero-stiffness isolator[J].Journal of Vibration&Control,2014,20(15):2314-2325.
[6]刘兴天,张志谊,华宏星.新型低频隔振器的特性研究[J].振动与冲击,2012,31(5):161-164.
[7]Zheng Y,Zhang X,Luo Y,et al.Design and experiment of a high-static-low-dynamic stiffness isolator using a negative stiffness magnetic spring[J].Journal of Sound&Vibration,2016,360:31-52.