模态

Then it compared the stress distribution and strain distribution of blades which is orthotropic material.

并比较了各向异性材料叶片的模态应力和模态应变的分布状态。

The eigenmode of the structure is solved using subspace iterative parallel method.

采用子结构模态综合算法，结构特征模态采用子空间迭代方法并行求解。

The finite element models of two types of machine guns are set up, mainly based on the 3-dimensional beam elements, partly based on boundary elements. Modal experiment plan of the machine guns is designed and their modal analysis experiments are done. The inherent properties of structural vibration and dynamic response properties for type-02 14.5 mm anti-aircraft machine gun and type-89 12.7mm machine guns are completely realized through the method combining theory and experiment, and many valuable conclusions are obtained.

建立了以三维梁单元为主，边界元为辅的高射机枪和重机枪有限元模型，设计了模态试验方案并进行了两支枪的试验模态分析，采用理论与实验相结合的分析方法，全面揭示了 02 式 14.5mm 单管高射机枪和 89 式 12.7mm 重机枪的结构振动固有特性和动力响应特性，获得了许多有价值的结论。

Based on the theory of modal superposition and power series expansion, a modal superposition method for the sensitivity analysis of FRF is proposed in this paper.

基于模态展开和幂级数展开原理，提出了一种频响函数灵敏度分析的模态展开法。

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。

Methods According to the principle of mode superposition,a method of structural dynamic modification was developed with the method of sensitivity analysis based on model test results.

利用基于模态试验的灵敏度分析方法，依据模态叠加原理，提出了一种结构动力修改思路。

Based on the concept of the non-proportional damping which may be divided into the proportional part for dissipation of energy and the nonproportional part for transformation of energy, a new modal superposition pseudo-force method is presented if the approximate decoupling method is not suitable. In this method the coupled modal equations are solved by iteration in which the coupling terms are treated as pseudo-force and set to the right side of the equations.

在不能进行近似解耦分析时，基于非比例阻尼可分为耗散能量的比例部分和转换能量的非比例部分这种概念，建立了一种拟力实模态叠加法，即把正则化的耦合模态方程中代表非比例阻尼部分的耦合项作为虚力，放到方程的右端，再运用迭代法求解。

The sliding mode control, which is better than the linear quadratic optimization, achieved ideal control result by using comparatively less external energy. The sliding mode control method is valuable to study.

基于模态分析的滑动状态控制比线性二次最优控制用较少的外部能量可得到较好的控制效果，基于模态分析的滑动状态控制是一种有研究、开发价值的控制算法和控制方法。

That is a random signal and vibration analysis system,the parameters and modal shape s are acquired.

3的模态测试分析功能对该柴油机机体进行了模态测试，得到了机体结构的前5阶固有频率及相应振型，可看出机体各部分振动的特征，据此为发动机结构改进设计提供了试验依据。

Many researchers have devoted their work to the development of modal analysis extraction techniques in order to obtain more reliable identification of the modal parameters. There are many damping identification methods, but each one has different merit and defect. In order to find which one is the most reliable method with respect to certain characteristics, this thesis focus on how to identify structure's damping in time domain. The following works have been done in this thesis: 1. Investigate four modal analysis methods——the LSCE Method, the Ibrahim Time Domain Method, the Time Domain Collectivity Modal Parameter Method, the Rational Fraction Polynomial Method and improve on the ITD Method in arithmetic.

本文主要做了如下工作： 1、集中研究了四种常用的模态识别方法，即最小二乘复指数法、Ibrahim时域法、时域总体模态参数辨识法及有理分式多项式法，并对ITD法在算法上进行了一定的改进； 2、建立结构动力模型，利用这四种方法在具体条件下识别结构的阻尼，并绘制相应的图； 3、讨论不同的情况下，不同的识别方法对阻尼识别精确性的影响； 4、基于业已明确的阻尼识别的精确性，根据研究的需要，指出在实际的识别过程中，如何选择最佳的识别方法以及识别过程中需要注意的问题； 5、选择最为精确的阻尼识别方法，以导师李书进教授在日本京都大学防灾研究所强震反应实验室所做的一足尺木制结构房屋的动力测试实验为实测模型，识别其阻尼； 6、在本文的最后，尽作者所知，提出了一些需要改进的地方，并对未来的研究方向给出了作者的建议。

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