模态的

A four\|node piezoelectric composite laminated plated element was implemented for dynamic analysis of adaptive structure. The damping ratios of truncated models were considered as the control objects, so that each of the structural modal oscillation could decay rapidly. Hence, the structural oscillation was effectively controlled.

利用四节点压电复合材料层合板单元进行自适应结构的有限元动力分析；采用模态控制方法，将结构的各阶模态的阻尼比作为控制目标，并以此计算出各压电片的控制电压，达到控制结构振动的目的。

Through elaborating theoretical basis of modal analysis,the value is researched about standard simple-supported damaged beam so as to find out the influence of different damage position on beam vibration modal and their correlation.

通过论述模态分析技术的理论基础，并对标准简支损伤梁振型的数值研究，可揭示出不同损伤位置对梁振动模态的影响，从而提出一种桥梁损伤诊断的新思路。

The result of optimization and analysis show: 1 across-axis sensitivity is smaller, less than 2% of the primary axis sensitivity; 2 the first mode is dominant at primary axis, which reduce intersectional coupling; 3 when damp ratio is between 0.3 and 0.7, accelerometer has better dynamic characteristic.

分析结果表明此种结构的具有：1横向灵敏度小，X、Z方向的横向灵敏度均不到敏感方向的2％；2在敏感方向上，一阶模态起主导作用，其它模态的影响较小，有利于减小交叉耦合的影响；3当阻尼比毛为0.3—0.7时，传感器具有较好的动态特性。

In this thesis, the methods for solving eigenvalue problems and conventional reanalysis methods are studied firstly. Then, a new reanalysis method for real modal reanalysis of structures subjected to topological modification with added degrees of freedom is presented. This method is composed of the single step perturbation method and the Rayleigh-quotient iteration. The numerical examples show that this reanalysis method is very effective and high-quality.

本文首先在对常规的特征值数值求解方法和重分析方法研究的基础上，针对实模态的自由度增加的结构拓扑修改重分析，提出了一种新方法，该方法由于结合了单步摄动法和瑞利商逆迭代法两者的优点，应当是一种比较理想的重分析方法，算例的数值结果也有力的验证了该方法确实是一种高精度、十分有效的实模态重分析方法。

In chapter Ⅰ, a historial review of structure control is given; In chapter Ⅱ, A discussion of the controllability and observablity of flexible structures is given, Two kinds of controllability and observablity index are defined, and applied to actuator allocation; chapter Ⅲ considers the reduction of high order flexible structure mode; the content of chapter Ⅳ is about the basic problem of distributed parameter control system design. It is proved that a stable controllor in mode space may be unstable in real use in distributed paramater systems, also, by closed loop mode concept, a pole assignment method of flexible structure controllor design is given; chapter Ⅴ is about the low-authority controllor design, it is pointed out by use of high order eigenvalue/eigenvector perturbation, a better controllor can be designed; chapter Ⅳ considers flexible structure reduced order control; chapter Ⅶ disscusses the basic problem of flexible structure computer control, analyses discreate controllablity and observablity and its computing, the sample period and coefficient wordlength; chapter Ⅷ is on the problem of low flexibility compensation; chapter Ⅸ is a design example.

在第一章简要回顾了挠性结构控制的历史，并且指出控制中的一些问题；第二章讨论了挠性结构的能控性与能观性，定义了两类能控性程度和能观性程度指标，还将能控性程度概念应用于执行器位置的确定；第三章论述了高阶模型的降价问题，比较了适于挠性结构模型降阶的方法，指出其适用范围；第四章内容是分布参数系统设计的基本问题，首先证明在模态空间中设计的稳定的控制器在实际分布系统上可能是不稳定的，进而根据闭环模态的概念，获得挠性结构控制器设计的极点配置方法；第五章的内容是关于低权控制器的设计问题，指出利用特征值高价摄动和特征向量的摄动，可以设计出更加完善的低权控制器；第六章讨论挠性结构降阶控制问题；第七章讨论挠性结构计算机控制的基本问题，分析了时间离散化模型的能控性和能观性及其计算问题，讨论了采样周期选择和系数字长问题；第八章讨论低挠性结构的补偿问题；第九章的设计例子用来说明第二章和第四章的结果。

This is a good application of laser measurement technology in the test of a car body mode, which overcomes the limitation of a single scanning laser vibrometer in the test of 3-dimension modal shape of a structure. The use range of the single scanning laser vibrometer is also expanded.

这是激光测振技术在白车身模态实验中的一个很好的应用，而且较好地克服了单头激光测振系统难于测试结构三维空间模态的局限性，扩展了单头激光测振仪的使用范围。

The three dimensional model on engine block combination structure of a piston engine is established by the ANSYS software,and the modal analysis is carried out in the case of constrained model.

采用ANSYS软件对某活塞发动机机体和缸盖的组合结构进行了约束模态的有限元分析，得到了机体组合结构的前20阶约束模态的固有频率及相应振型。

The perturbation methods are the common analyzing method for studying thevibratory response of the mistuned bladed disk, but different perturbation methodshave their own relying conditions on the system parameters. In this dissertation, threekey perturbation methods are studied for their application conditions. Their relyingconditions on the system parameters are summarized.

本文对三种常用摄动法的构造特点及其适用性进行了研究，总结了它们在分析失谐叶盘系统振动响应时对于系统参数的适用条件；针对自适应摄动法在分析失谐叶盘系统振动响应时，对于基系统模态的选择难以控制的问题，提出了一种模态自动选择法。

Therefore, the choice of single mode in the examination and the frequency-thick band of mode has been given a particular illumination separately in the paper, following a relative numerical simulation. And a multi-cyclical sine signal modulated by Hanning window is used to simulate the excitation wave, and then an inspected ring of nodes is established to receive the echo, finally how the length of the circumferential cracks, the width of the axial cracks and the degree of the thickness-reduce effect the result is explained through the analysis of the result, further more, the reflection factor in the defect has been calculated.

因此，本文也就单一检测模态的选择以及模态频厚积段的选择分别予以了阐述，并有针对性的进行了数值计算：应用Hanning窗调制的多周期正弦波模拟单音频激励信号，并设置监测质点环接收回波，通过分析说明了管道的周向裂纹、轴向裂纹以及点蚀缺陷对缺陷回波所产生的影响，并进一步计算了缺陷处的反射系数。

All the above research forms the basis theory system of vibration theory modality and experimental modal for the light thin plate retaining wall system and its health diagnose technology.

通过本文的研究，形成了轻型薄板挡土墙系统振动理论模态与试验模态的基本理论体系以及健康诊断的分析技术。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷