查询词典 damping

In the first part, it discusses the existence of global weak solutions of the initial boundary value problems to a class of multidimensional quasi linear evolution equations with strong damping, nonlinear strain, nonlinear damping and...

我们证明，上述方程中诸非线性项的增长阶（假定它们均具有不超过多项式的增长阶）指数、初始能量的状态和相应的定解问题的整体解存在与解在有限时刻发生Blowup现象之间存在着密切的联系，得到了增长指数、初始能量的状态与整体。。。

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。

ABSTRACT:The half-power bandwidth method is the commonly used method at home and abroad, the authors discover that factors, such as the sampling frequency, the frequency resolution, the ratio of the sampling frequency to the signal frequency, the analyzed width and the damping ratio, make the estimated damping ratio fluctuate vastly. Mostly the result is incredible except for some conditions, the error is sometime amazing, which is not acceptable.

半功率带宽法是国内外常用的测试阻尼的方法，笔者发现半功率带宽法由于受到信号处理中的①采样频率SF②频率分辨率△f③采样频率与信号频率之比K ④采样分析的长度T和⑤阻尼比D的大小等因素的影响使得测得的阻尼比值波动很大，除少数状态是可信的外，多数状态是不稳定的，有时误差惊人，得到的测试数据不能使用，易导致错误的结论。

The effect of pre-deformation on the damping capacity was studied and the effect of the movement of Shockley partial dislocation on the damping capacity of FeMnCr alloy was analyzed by dislocation theory.

研究了不同的预变形量对FeMnCr合金阻尼性能的影响，并根据位错运动理论，分析了 Shockley不全位错的运动对该合金阻尼性能的影响。

Chapter four studies the chaotic responses in a system consisting of simple pendulum and harmonic oscillator under bounded noise excitation. Firstly, the Melnikov function of the two-degree-of-freedom system under Hamiltonian perturbation is derived. The essential condition of the autonomous system for the probable onset of chaos is obtained, the Poincare maps of the system under small Hamiltonian perturbation and the effect of increasing perturbation on the Poincare maps are studies. Then for the non-autonomous system under damping and harmonic or bounded noise excitation, the largest Lyapunov exponent and Poincare maps are calculated. From the analysis of the largest Lyapunov exponent, the critical criterion for the onset of chaos, and the conclusion that the threshold of bounded noise amplitude for the onset of chaos in the system increases as the intensity parameter of Wiener process increases are obtained. The result from the analysis of Poincare maps is in agreement with that obtained from the Largest Lyapunov exponent. The effect of varying damping coefficient and intensity parameter of Wiener process is also analyzed.

第四章研究了有界噪声激励下的两自由度单摆—谐振子系统的混沌运动，首先推导了该两自由度系统仅在Hamilton扰动下的Melnikov函数，得到该自治系统可能产生混沌的必要条件；研究了该系统在小的Hamilton扰动和增大摄动情形下的Poincare截面；然后对有阻尼、谐和或有界噪声激励下的非自治系统数值计算了其最大Lyapunov指数和Poincare截面；从Lyapunov指数分析得到了这个两自由度系统产生混沌运动的临界条件及产生混沌的临界激励幅值随Wiener过程强度参数值的增大而增大的结论，Poincare截面分析的结果亦符合Lyapunov指数分析的结论；研究了Wiener过程强度参数、阻尼系数变化对Poincare截面的影响。

Considered the factor of damping,a single degree of freedom s dynamic model of the high-speed cam mechanism is established.Choosing the law of sine acceleration motion as the excitation function,a displacement and acceleration dynamic response equations of the main vibration phase and residual vibration phase,the working dynamic response change curve through the inferential reasoning working end movement equation is derived.The result is obtained that different period and damping ratio have different impact

建立了考虑阻尼因素的等效单自由度高速凸轮机构的动力学模型，以正弦加速度运动规律方程为激振函数，推导出了从动件系统主振段和余振段的位移和加速度动态响应方程并绘制出了动态响应变化曲线，得出了不同阻尼比和周期比对主振段和余振段的动态响应，从而为高速凸轮机构的合理设计提供了一定的理论依据。

The article put forward "the equivalent linearization methed for the nonlinear damping in the stationary random process" in order to solve the problems of nonlinear damping, which is widely adopted in automobiles.

为了解决汽车上广泛采用的非线性阻尼问题，文中提出"平稳随机过程中，非线性阻尼的等效线性化方法"，并给出一般形式的解答。

The effects of trace Ce and La on the damping capacity of aged Zn-22%Al have been studied using TEM,SEM and room temperature low frequence torsional pendulum damping meter.

采用自然时效、人工时效等热处理工艺，借助透射电镜和室温低频扭摆内耗仪，研究了微量Ce，La对高阻尼Zn-22%Al合金时效后显微组织和阻尼性能的影响。

The influence of structural damping coefficients on the peak value of the response of the vibration generator was investigated to determine the damping parameter according to the calculations of frequency response on the vibration generator.

通过对仿真模型进行频率响应计算，研究了阻尼对振动台响应峰值的影响情况，确定了各阻尼系数的取值。

The behavior and performance of the MR valve with both annular and radial damping gaps is expressed in terms of non-dimensional parameters and the efficiency of the MR hydraulic actuator system with the MR valves with both annular and radial damping gaps in Wheatstone bridge network is studied

同时推导了基于平板模型的同时具有圆环和圆盘阻尼间隙的磁流变阀的非量纲的体积流量，得到了桥式连接的磁流变阀工作时驱动泵效率的计算模型。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。