模态

The static natural frequencies and dynamic frequencies (under 3000rpm) are calculated by the finite element method and cyclic symmetry technique. The rotating vibration behaviors of the two models are compared. Different vibration characteristics between the two models are discussed. Geometry mismatch in a turbine blade root, which arose in manufacturing process or caused by wearing out during service, leads to contact conditions changed in fir-tree attachments. As a result, shifting of the fundamental frequencies and redistribution of stress in the blade base possibly cause failure of the blade.

在叶片—轮盘耦合系统振动研究方面，建立了带围带的叶片振动计算模型和带围带的叶片—轮盘耦合系统振动计算模型，考虑旋转离心力作用，采用波传播技术，对两种模型分别进行了整圈模态分析，得到了某汽轮机叶片模型和叶片—轮盘耦合模型在0转速和工作转速(3000rpm)下的振动模态，并对所得结果进行分析比较，讨论了整圈叶片振动模态与叶片—轮盘耦合振动模态的区别。

By using the modal superposition method for the dynamic responses calculation of the linear oscillation system, a judging indictor in the energy norm form is given to determine the number of dominant modes on mode truncation.

针对用模态叠加法计算结构线性振动系统的响应，作模态截断的截尾模态阶数的取值，给出了能量范数形式的判断指标。用于小湾拱坝结构的动力分析表明，需取 10阶以上的模态进行叠加

It is often seen that only lower order modes of the beam without large overallmotions are chosen to reduce the number of the generalized coordinates,the simulation,however,is able to reach certain accuracy.

本章对不同转速和中心刚体半径下模态截断法和有限元法的仿真结果进行比较，根据两种方法的振动基频的相对误差确定了模态截断的阶数与转速、中心刚体半径的关系，提出了模态截断的准则，解决了模态截断法的精度问题。

The project proposed and established the strict unique mathematical model of instantaneous frequency aiming at the currently existed problems in Hilbert Huang Transform form the viewpoint of physical connotative meaning; proposed and established the strict mathematical model of general intrinsic mode signal based on the concept of general continuous intrinsic mode signal and the compositive principle of practical general intrinsic mode signal; researched and proposed the fitting method of envelope lines in HHT from the viewpoint of theory, conquered the blindness and random in quondam EMD envelope line fitting and boundary treatment; developed a virtual time-frequency analyzer based on general intrinsic mode signal decomposition to open out the local time-frequency characteristics of nonlinear and nonstationary signal more deeply and accurately.

本项目针对希尔伯特-黄变换现阶段存在问题，从物理内涵的角度提出并建立了瞬时频率严格的唯一的数学模型；基于连续性的一般固有模态信号的概念和实际信号的一般固有模态信号的组成原理，提出并建立了一般固有模态信号严格的数学模型；从理论角度研究并提出HHT中的包络线构造方法，克服了原EMD的包络线构造和边界处理的盲目性和随意性；研发一台基于一般固有模态信号分解的虚拟式时频分析仪，使之可以更深入、准确地揭示非线性非平稳信号的时频局部特征。

Firstly, the 3D solid model of the analyzed object is built directly in the FEM software ANSYS 8.0 without using other CAD software. The influence of the side sizes of solid elements on computing results and the influence of coupling ways between different parts on the modal parameters are researched by simply modeling. And a new connecting method about joints in ANSYS is proposed and applied to finite element modeling of the test-bed for spindle system. Furthermore, several different computing techniques for modal parameters extraction are compared in solving the finite element model of spindle system test-bed. Many modal solutions are also done to achieve the relationships between the whole or part stiffness value and computed modal parameters. The laws about joint rigid parameters" influences on modal parameters are discussed by means of altering their values for conjoint parts. And by changing local rigid parameter values, the different location selections" influence on computed modal parameters is also studied.

本文通过使用ANSYS 8.0软件直接建立研究对象的实体结构模型，而没有借助其他的CAD软件；通过构建简单的模型研究实体单元边长大小对计算结果的影响，部件之间不同的联结方式对模态参数的影响，探讨在ANSYS中实现结合部的方法，提出一种新的联结方法，并建立主轴系统试验台的有限元模型；对建立的主轴系统试验台有限元模型求解，比较几种不同模态提取方法；通过改变结合部联结单元的刚度参数进行的计算，寻找联结刚度对模态参数变化的影响规律；改变局部联结单元的刚度参数，研究刚度值位置差异对计算模态参数的影响。

In this study, we used the couple-mode theory for the simulation. We select the profile index of multimode fiber, profile index of mode conditioning patch cord and VCSEL output power as parameters for the simulation. The influence of using mode conditioning patch cord to the modal noise and modal coupling efficiency is showed.

利用模态耦合理论(Couple-Mode Theory)搭配多模光纤之折射率分布指数、多模模态调整转换跳接线之折射率分布指数及面射型雷射之模态分布，作为模拟计算依据，并利用OptSim模拟软体来模拟850nm面射型雷射与50μm多模光纤之光输出耦合情形。

First, this paper presents three girders model with double cable planes which main girder and side girder is connected by rigid arms, analyzes the dynamic characteristic of Yonghe cable-stayed bridge and obtains its natural vibration modes (i.e., frequency, damping values and the mode shapes ) by ANLSIS structural analysis program and uses these parameters as dynamic dactylogram of the intact case of cable-stayed bridge. Using the passage of random as the ambient vibration ,the dynamic properties of Yonghe Bridge is measured and the modal parameter of its 15 years after is identified and used as dynamic dactylogram of the damaged case. By the finite element analysis and locale vibration test, damaged and undamaged modal parameter is analyzed and curvature mode shape, which is sensitive to damage state, is introduced as possible candidate for identifying and locating damage in the cable-stayed bridge. Selecting the branch of part measured point from modal parameter, this paper deduces the damaged index which can detect the possible damaged location of the cable-stayed bridge deck and identifies the damaged region and degree for Yonghe Bridge. For the purpose of structural condition monitoring in in-situ , from another viewpoint, this paper introduces the method called the best optimization vector to detect damaged location and degree. The accuracy and reliability of the method presented in this paper are demonstrated by static analysis and test and the healthy state of Yonghe Bridge can be evaluated.

建立了双索面通过刚臂与主梁及边梁相连的三梁式力学模型，采用ANSYS结构分析程序对永和斜拉桥进行动力分析，对其振动模态参数进行识别，以此作为斜拉桥完好状态下的动力&指纹&；采用自由交通流作为环境振源，对永和斜拉桥动力特性进行测试，识别出永和斜拉桥使用15年后的模态参数，确立了破损状态下的动力&指纹&；利用有限元分析、现场振动测试，对破损前后的模态参数进行分析，提取对破损状况较敏感的模态曲率作为斜拉桥破损诊断的参数；并从模态参数中选取部分点的分量，导出可以指示斜拉桥桥面大概损伤位置的Index损伤指标，识别出斜拉桥发生破损的区段及破损程度；考虑大型斜拉桥在线监测要求识别破损的具体位置，从另一角度提出采用最优矢量法具体确定破损发生的位置及程度；为验证本文研究成果，对永和斜拉桥进行静力分析及静力测试，对其健康状况提出可靠的评价。

First, modal resolution of the cabinet is obtained by ANSYS modal analysis; Then, modal experiment of cabinet is carried out with impulse excitation method and corresponding modal parameters are obtained.

首先，采用有限元软件ANSYS理论模态分析对机箱进行模态求解，得到计算模态参数；另外，用脉冲激励法对机箱进行模态实验，得到实验模态参数。

Spatial pattern of the sea surface temperature appears a basin mode consistent with the isobaths in SCS, while the wind field exhibits a weak winter or summer monsoonal characteristic. The MOCM in different season may reflect a positive SST-evaporation-wind feedback which may be stronger in winter than in other seasons.

结果发现；第一模态为最显著模态，模态协方差贡献比在四季均超过80%，空间上SST表现为与南海等深线相一致的海盆模态，风场上主要表现为弱的冬季风或弱的夏季风，各个季节的海－气耦合模态都主要反映了SST-蒸发－风反馈这样1种正反馈的海－气相互作用过程，而且冬季风期间这种相互作用要更强烈些。

The strainpath analysis indicates that the deformation of the sheet at the fracture location changes into the plane-strain mode from the stretch mode as the die corner radius is further increased from the optimum value, resulting in an early fracture since the plane-strain mode has a lower forming limit as shown in the FLD of Fig.

当一钢模角落半径是进一步的增加时候调查揭露 formability 是改良的如一钢模角落半径直到最适宜的价值增加，而且变得更更坏地。strainpath 分析指出张的毁坏在破碎位置变化是进入如一钢模角落半径的来自可伸缩的模态飞机-紧张模态之内比较远的从最适宜的价值增加，造成一个早的破碎因为飞机-紧张模态有如图 2 的 FLD 所显示的一个比较低的形成界限。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。