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Some basic concepts about the active structures were firstly explained, and the main subjects to study in the field of active structure dynamics were synthesized. For the linear active structures, the annotations on the modes were done in detail. The physical meanings of the right and left eigenvectors were explained. The right eigenvectors are the modal shapes and the modal responses of an active structure depend on the left ones. The adjoint structure of an active structure was defined and the reciprocity theorem was interpreted. For two active structures, which are adjoint to each other and with the reciprocal gain-matrices, the right and left eigenvector are reciprocal. The relationship between an active structure and the corresponding passive structure is expressed with the transfer functions, which is employed to resolve the estimation problems. 相似文献
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王永刚 龚靖School of Civil Engineering Mechanics Xi'an Jiaotong University Xi'an P.R.China Department of Civil Engineering Northeast China Institute of Electric Power Jilin P.R.China 张景绘School of Civil Engineering Mechanics Xi'an Jiaotong University Xi'an P.R.China 《应用数学和力学(英文版)》2004,(8)
IntroductionThestudiedobjectintheclassicstructuredynamicsisthepassivestructureswhicharechangedintoactivestructurewhencontroldevicesorsmartmaterialsareintroducedintoandthecontrolfunctionisapplied .Anactivestructureisgenerallycalledactivesystem .Asforthedefinitionofactivestructure ,itistheconceptofworthydiscussion[1].Thedefinitionshouldbebecomingrigorouswiththestudyontheactivestructuraldynamics.Withincertaincategoryofactivestructuresinpaper (Ⅰ ) [2 ],someattributesaboutthemodesoflinearactivest… 相似文献
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水下发射导弹在出、入水以及水下运行过程中,由于流体、水动力以及运动速度的影响,产生附加质量和轴向荷载作用,影响结构振动频率.本文针对水下高速运动结构,给出了流体影响、轴向荷载分别作用以及二者同时作用下,结构频率的固有频率计算方法;并从理论分析、数值模拟和实验研究三个方面对水下的结构的固有频率进行了分析和研究.近似计算表明计算结果具有较好的一致性,而且由于流体和轴向荷载的影响,结构的固有频率有明显下降的趋势,而且对低阶频率影响较大. 相似文献
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The basic concepts about the active structures and some attributes of the modes were presented in paper "Liner Active Structures and Modes ( Ⅰ ) ". The characteristics of the active discrete systems and active beams were discussed, especially, the stability of the active structures and the orthogonality of the eigenvectors. The notes about modes were portrayed by a model of a seven-storeyed building with sensors and actuators. The concept of the adjoint active structure was extended from the discrete systems to the beams that were the representations of the continuous structures. Two types of beams with different placements of the measuring and actuating systems were discussed in detail. One is the beam with the discrete sensors and actuators, and the other is the beam with distributed sensor and actuator function. The orthogonality conditions were derived with the modal shapes of the active beam and its adjoint active beam. An example shows that the variation of eigenvalues with feedback amplitude for the homo-configuration and non-homo-configuration active structures. 相似文献
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利用非平稳信号的时频分析方法研究了一类非线性系统的频率特性和阻尼特性随运动形态的变化规律,得到了能简洁、直观地反映系统基本非线性动力学特性的广义骨架线性系统(简称GSLS)和骨架曲线。在此基础上,利用时频滤波方法根据系统非平稳响应信号对非线性系统进行辨识。该项工作为非线性系统反问题的研究提供了一条新的途径。 相似文献
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I.IntroductionThemaximumresponseofastructureisoftenusedasthebasisfordesigning.Drenick(l968,l97o),Shinozuka(l97O)andmanyotherauthorshaveusedthemaximumresponsetoseismicexcitationasadesigncriterion.Theresponse-spectrumtheoryinseismicdesignisalsobasedonthemax… 相似文献
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建立具有压电分流阻尼的连续梁的动力学基本方程,推导出适用于各种不同分支电路构型的广义传递函数,并推导出对应于三种不同分支电路的电器元件最优参数表达式。对三种不同分支电路的减振特性进行理论分析和比较。分析结果表明,LR并联和LR串联分支电路可以有效地减小振动幅值,并具有相同的减振效果。在LR-C并联分支电路中,通过附加一个电容,可以减小最优设计时所需的电感值,但是减振效果降低。本文为连续梁的压电分流阻尼系统的减振设计提供了有效的方法。 相似文献
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本文首先讨论工程振动信号频谱再分析技术,针对所存在问题,提出模糊式识别再分析方法,以滚动轴承振动成因研究中的谱分析为例,具体介绍了频谱的峰值频率分布模式,模糊子集及隶属函数的确定,以及综合评判的识别过程,最后给出一具体计算结果。 相似文献
10.
Some basic concepts about the active structures were firstly explained, and the main subjects to study in the field of active structure dynamics were synthesized. For the linear active structures, the annotations on the modes were done in detail. The physical meanings of the right and left eigenvectors were explained. The right eigenvectors are the modal shapes and the modal responses of an active structure depend on the left ones. The adjoint structure of an active structure was defined and the reciprocity theorem was interpreted. For two active structures, which are adjoint to each other and with the reciprocal gain-matrices, the right and left eigenvector are reciprocal The relationship between an active structure and the corresponding passive structure is expressed with the transfer functions, which is employed to resolve the estimation problems. 相似文献