查询词典 time of vibration

Firstly, this paper investigated roundly the basic theory of the ambient vibration method, analyzed systematically the main methods of ambient vibration identification, and discussed their advantages and disadvantages. Then we established the finite element model of structural dynamics and test model and analyzed their mutual relation, improved MUSIC method and correlation function method in the harmonic identification, and gave the subspace method and correlation function method based on continuous model, which is multi-harmonic retrieve technique. And then, this paper also puts forward least-squares method to estimate directly structural physical and modal parameters; this approach replaced the derivative operator in the continuous time model with an equivalent approximation, and estimated the physical parameters of structures by the least-squares method. And then, we discussed the approximation methods of derivative and their convergence. Finally, this paper researched the modal parameters of a frame structure by the simulation and test. The results demonstrated that subspace method, correlation function method and the least-squares method are effective and stable respectively.

全面地研究环境振动识别方法的基本理论，系统地分析环境振动识别方法的主要方法，讨论它们的优点和不足；建立结(来源：6666AB44C论文网www.abclunwen.com)构动力学的有限元模型和试验模型，分析有限元模型与试验模型之间的相互关系；改进谐波识别中的MUSIC识别方法和相关函数识别方法，给出大型结构模态识别的连续型的子空间分解识别方法和相关函数识别方法，这个方法是多元谐波识别方法；提出直接识别结构的物理参数和模态参数的最小二乘方法，这个方法利用导数的近似值代替导数值，并运用最小二乘方法识别结构的物理参数，讨论导数近似值的选择方法，分析算法的收敛性；通过仿真计算和模型实验，研究高层框架结构的模态参数识别，验证子空间分解识别方法、相关函数识别方法和最小二乘识别方法的有效性，算法的稳定性；从理论和试验两个方面分析和研究噪声对识别精度的影响，影响识别精度的因素，以及部分模态成分的模态参数不能够被识别的原因。

Based on a series of signal process and noise source identification techniques, especially the major noise source identification methods, such as expurgation method, sound intensity analysis, spectrum analysis vibro-acoustic correlation analysis and so on, the pass-by noise control of SC7080A and SC6360B are studied in detail. By the roadway and dais experiments, the major noise and radiating parts are identified and some economical controlling methods are made. For the SC7080A, to control the emissing noise from the intake and shell vibration of air cleaner, a intake muffler is installed between the air cleaner and intake valve. Based on the theory of Helmholtz resonator, One three-parallel-connected resonant silencer is designed and trial-manufactured. For the SC6360B, the attenuation performance of exhaust muffler in high frequency region is improved. To reduce the vibration noise of shell part, the structure of oil sump tank, exhaust manifold shield and exhaust manifold shield are analyzed and improved. At the same time, some measures, such as sound absorption, sound insulation, are taken to reduce the noise of engine surface emissivity and a sound shield is designed.

本文首先综述了目前国内外汽车加速噪声控制的现状、主要方法和技术措施，在此基础上，结合SC7080A和SC6350B汽车的车外加速噪声水平及现状，综合运用分别运行法、声强法、频谱分析法、声振相干函数法等现代噪声源识别方法，对SC7080A和SC6360B汽车进行了准确详细的车外加速噪声源识别并提出了经济可行的控制方案，针对SC7080A，主要在空气滤清器和进气阀门之间的进气管道上加装进气消声器，抑制空气滤清器壳体表面和进气口两处的噪声辐射，根据Helmholtz共振腔原理设计了三腔并联旁支型共振消声器，并进行了工程化设计和试制；针对SC6360B，主要改善了排气消声器在高频段的消声性能，对罩壳类零件进行了结构改进，降低了其表面噪声的辐射，并对发动机舱进行了吸声、隔声处理，设计了发动机隔声罩。

The time-frequency analysis of nonstable torsional vibration signal and multiresolution analysis based on wavelets of torsional vibration signal are introduced in chapter 5 and chapter 6 respectively.

第六章着重讨论了小波分析在扭转振动信号的频带分离和噪声滤除中的应用。

At the same time, the approximate shock vibration is produced, which let us to have a new idea to study a new-type shock vibration road roller.

同时通过改装压路机使其产生准冲击振动，也让我们有了研制新型冲击式振动压路机的思路。

So we designed a adaptive synchronizing controller based on hereinbefore hardware environment: first a small magnitude reference signal r is outputted to system through the signal card (to ensure that the vibrating system works in a linear state), and this signal is sent to the moving coil of vibrator through the power amplifier, so vibration is produced through electromagnetic induction. Secondly the vibration signal can feedback to the data acquiring card in the servo system through the acceleration sensor on the Vibroseis reactor M〓 and the base-plate M〓, then the computer can get the current vibrating state y〓 of the coil of vibrator according to the feedback information from the data acquiring card, and give a real time comparing between the current state y〓 and the reference output y〓 of the set-in reference model with current reference input being r , then regulates the correlative controlling parameters according to the error e〓=y〓-y〓 till y〓→y〓, finally normal signal sweeping begins with a certain phase fixed. Meanwhile a synchronization signal for seismic signal record is sent to seismograph from synchronization signal outputting component in the Vibroseis system to perform the controlling process of synchronization of sweeping phases.

为此，我们基于以上的硬件环境设计了一个自适应同步控制器：首先通过信号发生卡对系统输出小幅度的参考信号r(从而保证振动系统工作处于线性状态)，信号通过前置放大器、功率放大器等送到激震器动圈，并通过电磁感应产生振动，振动信号通过可控震源激震器反应块M〓和基板M〓上的加速度传感器反馈给伺服系统中的数据采集卡，工控计算机根据采集卡的反馈信息，获取当前激震器动圈的振动状态y〓，并实时地将该状态与内置的参考模型在当前参考输入r下的参考输出y〓进行辨识，再将两者输出误差e〓＝y〓-y〓对系统的有关控制参数进行调整，直至y〓→y〓，最后在经过某一固定的相位后，开始信号的正常扫描过程，与此同时，由可控震源系统的同步信号输出部件向地震仪送出一地震信号记录同步信号，进而完成扫描相位同步控制过程。

Secondly, the cutter of the machine was studied from reducing vibration, emphasis on knives array, homeostasis. To apply "ANSYS"method, At the same time, it was known that inherent frequency of the main axis was so far higher than vibratory frequency, and the machine main axis'rotational speed won't cause sympathetic vibration.

其次，本文从减少振动入手对9LRZ-80型秸秆揉切机的关键部件切碎器进行分析，着重对动刀片的排列、动平衡等进行分析研究，并通过有限元分析，得到切碎器主轴固有频率远远大于机器振动频率，机具的转速不会造成共振的危害。

By using the transfer matrix method of multibody system, the hard problem of computation of the vibration characteristics of LRMLRS coupled with rigid bodies and elastic bodies is solved which is very difficult to the ordinary dynamic methods, and the vibration characteristics of LRMLRS which is varied when the number of rockets in the launch device is varied, is obtained conveniently. By developing augmented eigenvectors of the LRMLRS and its orthogonality conditions, the nonorthogonality problem of the multibody system including rigid bodies and elastic bodies is solved and the exact analysis of the dynamics response of the LRMLRS including rigid bodies and elastic bodies is realized. By using the random integer programming method, the hard optimization problem which contains continuous variables, discrete variables and random variables at the same time is solved. This method provides a technology for optimum design with random variables and discrete variables. The dynamic optimum design is realized to decrease the number of rockets consumption in the LRMLRS test. The simulation system of dispersion of fire is established by using the maximum entropy method to estimate dispersion of fire.

通过应用多体系统传递矩阵法，解决了刚弹耦合远程多管火箭多体系统振动特性这一通常力学方法不便于解决的计算难题，方便地获得了远程多管火箭振动特性及其随发射架上火箭弹个数变化而变化的情况；通过构造增广特征矢量及其正交性条件，解决了刚弹耦合多体系统特征矢量不具有通常意义下的正交性的难题，实现了对刚弹耦合远程多管火箭动力响应的精确分析；应用随机整数规划法，解决了同时考虑连续、离散和随机变量等多种设计变量的优化设计难题，为含随机和离散变量的优化设计提供了手段，实现了减少远程多管火箭试验用弹量的动态优化设计；建立了应用最大熵法估计的密集度仿真系统，优化射序和射击间隔，实现了提高远程多管火箭射击密集度的动态优化。

In this paper,researches were made on aspace piezoelectric truss.First,based on the piezoelectric theory and FEManalysis and knowledge of active vibration control,theoretical analysis and numerical simulation was carried on.And then,an experiment upon real-time active vibration control of the truss by computer was carried out.

本文以一空间压电桁架结构为切磋工具，应用压电表面、有限元分析和振动自动节制的相干常识，在清楚的表面分析和谋划机仿真的根本上，用尝试验证的方法对空间压电桁架结构的振动进行谋划机及时自动节制。

Fist, mode analysis is accomplished, and stiffness influence of the structure by the member parameter and the accessional columns are analysed. Then the numerical value of the pulsoting wind load was used, the time history contrastable analysis between mega-sub controlled structure and general megaframe structure has been accomplished. Finaly, the influence of vibration-controlled efficiency under the different member parameter of vibration-absorption megaframe structure is analysed.

首先进行了模态分析，讨论了钢筋混凝土巨—子型控制结构的主要结构参数及附加柱刚度对结构整体刚度的影响：利用脉动风荷载计算机模拟的荷载值，并对它和一般的巨型框架结构进行了脉动风荷载下的时程对比分析，讨论了钢筋混凝土巨—子型控制结构的主要结构参数对减振效果的影响，研究了钢筋混凝土巨—子型控制结构的动力特性。

Firstly, achieving a new low and high cycle noninterfering loading, the high frequency induction local heating, the control of high cycle vibration frequency and amplitude, and the crack propagation real-time detection, an experimental system of L-HCCF at elevated temperature is established. Secondly, under two vibration frequency (50Hz and 100Hz), the contrast experiment of light and serious corrosion disc slots is done. It is found that the experimental L-HCCF life of serious corrosion disc is less than that of light's, but its dispersion is larger, and the experimental failure is identical with the service's.

首先，进行大量试验工作，提出了高低周疲劳载荷的新型加载方案，并解决了高频感应局部加温、振动调频及裂纹实时监测等多个技术难点，建立了涡轮盘全尺寸高温复合疲劳试验系统；验证试验做到了故障再现；接着进行了两种频比（振频50HZ与100HZ）的轻、重腐蚀盘的对比试验；由对榫槽第一齿进行裂纹实时跟踪，得出了枞树型榫槽的复合疲劳裂纹扩展特点规律；对榫齿断口进行的金相分析表明：裂纹首先由第一齿开始，断口系复合疲劳；试验结果显示：重腐蚀盘试验寿命较轻腐蚀盘有显著的下降，而且分散性较大。

I'm going tor her!

我这就去救她！

As rise are design to help keep a several toney , a brain chemical at continues lever.

SSRI被设计来帮助保持血液中的复合胺即在大脑中一个连续水平的化学物质。