模态

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。

From this experiment, frequency response function could be found, and modal parameter also could be known by curve fitting, then compared with the differences of mode shape and natural frequency by using those modal parameters, also compared with finite element analysis, the results could be applied to detect the structure of beams and prevent it from damage and corrode for the safety in the future.

将实验中三种驱动器搭配加速度计实验分析结果较佳的一组方法，来从事结构之非破坏检测，探讨当固定梁有缺陷产生时，其结构之自然频率与模态振型的变化，并比较其不同缺陷处之固定梁实验模态结果，将来可应用於梁结构物损坏或腐蚀时侦测其安全性之分析。

A theory of cross correlation function s is developed in this paper that the cross correlation function s can be expressed as summations of decaying sinusoids as the impulse response functions under white noise excitation.

对互相关函数理论的进一步发展作了详细推导，探索出一条将互相关函数理论同多种经典模态分析方法相结合进行环境激励下模态分析的方法。

A method of cross power spectral density between responses is derived and a poly reference modal analysis method using cross power spectral density method in frequency domain is presented in this paper.

对各测点响应的互功率谱密度函数进行了详细推导，提出了一种基于互功率谱密度的频域多参点辨识法，这意味着许多原本利用频响函数的传统频域识别法可以很容易地用于工作状态下的模态识别，大大开阔了未知激励下模态识别的视野。

The characters and reasons of PIO are introduced. Taking an aircraft's PIO as an example, the PIO's principle (the more than 180 degs lag of the normal load behind the stick force, and the coupling of the pilot and the aircraft's short period mode) is analyzed.

介绍了产生驾驶员诱发振荡的原因，并以某飞机发生PIO为例，分析了产生PIO的机理——法向过载相位对纵向杆力的滞后接近于180°，驾驶员模态和飞机短周期模态出现了严重耦合。

Moreover, when the normalized damping matrix is diagonally dominant, it is strictly shown that decoupling the modal equations by neglecting the off-diagonal elements indeed minimizes the error upper bound.

同时，还严格地证明了，当正则化的模态阻尼矩阵是对角占优时，由忽略其非对角线元素使模态方程解耦的方法所引起的误差的上限的确能达到最小。

Signal analysis;parabola parameter spline curve;Empirical Mode Decomposition;Intrinsic Mode Function;Hilbert transform

信号分析；抛物参数样条曲线；经验模态分解；固有模态函数；希尔伯特变换

Parameter identification and load identification on basis of frequency-domain are all researched very well, while the error of truncation, which is brought by data conversion, can"t be avoided. So, how to avoid these errors and identify the structure"s modal-parameter and exterior-load accurately will be the key technique of this field in the future, and some research work shall be done in time-domain.

针对模态参数辨识、动态载荷识别的频域方法较为成熟，但频域法中数据变换带来的截断误差却无法避免的现状，着重对模态参数辨识，尤其是动态载荷识别的时域方法作了一定的探讨。

By means of the expansion theorem, the displacement is expressed as the summation of the first several exact modal vectors.

考虑前若干阶线性振动模态，使用展开定理，将索的位移表示成共轭的模态函数的级数和。

These modes are calculated in the paper by wave equation, finite element equation and model established, and computer procedure.

本文通过推导的压力波动方程、建立的有限元方程与计算模型、编制的计算机软件，计算出燃烧压力波动的多阶模态及各模态下的压力分布。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。