查询词典 natural vibration

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。

The governing equation of in-plane vibration of cable-restraint system is derived by means of D'Alembert principle, and then those partial differential equations are transformed into a set of ordinary differential equations by Garlerkin method. The method of Runge-Kutta integration is applied to solve the equation. The simulation analysis is made to prove that this vibration control has obvious damping effects and then the influence of cable tension, support mass, natural frequency and spring stiffness on the damping are discussed. Eventually, the approximate analytic solution of the optimum damping parameter is obtained to provide a simple and effective reference and design method for the engineers.

通过D'Alembert原理建立拉索－弹性约束系统振动方程，通过Galerkin方法将偏微分方程转化为常微分方程，应用龙格－库塔积分法求解方程；经过仿真分析，验证了该振动控制具有明显的减振效果，并且讨论了初始拉力、支座质量、振动频率及弹簧刚度对减振效果的影响；最后给出了计算最优阻尼参数的近似解析式，为工程师提供了简便有效的参考依据及设计方法。

Characteristics of free vibration and forced vibration of a damped system with dry frictional damping,viscous damping and c x·2 damping are analyzed and calculated,acceleration response of free-vibration of the dry frictional damped system has a sudden change when x· is zero,the change value is constant and depends only on the natural frequency ωn and the displacement xk due to dry friction.

本文对存在干摩擦阻尼、粘性阻尼和c.x2阻尼系统的自由振动及受迫振动特性进行了解析及数值计算，得到干摩擦阻尼系统自由振动的加速度响应在速度零点有一突变，这一变化量为定值，且只与系统固有频率ωn及摩擦当量位移xk有关。

The equations of dynamics for the balance are established by Kane's method, from which derives the characteristic equation of natural frequency by means of linearization of dynamic equations, and the six natural frequencies being developed according to the theory of vibration. The law of the six natural frequencies varying with mass of the upper platform and the stiffness of the elastic element are presented,and the Finite Element Method is employed to testify the validity of theoretical results.

基于 Kane 方法研究天平的动力学及模态，通过线性化动力学方程建立天平的固有频率方程，依据振动理论推导出并联天平的六阶固有频率及其对应的振型，同时研究了天平的六阶固有频率随敏感单元刚度系数及上平台质量的变化规律，并用有限元法验证理论计算结果的正确性。

Application of proportional controller to active vibration control incorporated with passive vibration isolator to suppress its resonant oscillation of natural frequency is proposed in this paper. Vibration acceleration acquired from accelerator is inputted to controller as feedback signal. The processed signal from controller is transmitted to voice coil actuator to control vibration.

本文主要是运用比例控制器进行被动式隔振系统自然频率共振抑制之主动控制研究，控制回馈讯号采用加速规量得之振动加速度值，经由控制器计算输出控制讯号驱动音圈致动器进行主动控制。

In the part of the vibration experiments and analysis, firstly, used the simple-beam theory to estimate the natural frequency of the beam of the 20-headed computerized embroidery machine.secondly, measured the beam of its low rank natural frequency, the beams horizontal vibrating acceleration amplitude, speed amplitude and the displacement amplitude in different rev and different turn parts. Found that it is sympathetic vibration, which bring on the thread-broken rate rise rapidly. On this base, established the finite element analysis modle of the vibrating beam, and took on hamonic analysis and modal analysis with the mold. The rusult of test and analysis offer the basis for farther improvement of the computerized embroidery machine.

振动分析部分，首先由简单梁理论出发，对横梁的固有频率进行估算；接着通过测振仪器对20头电脑刺绣机横梁进行了试验模态分析和不同工况振动测试；获得了横梁前四阶固有频率和模态振型，以及在不同工作转速、不同回转部件下横梁振动的加速度幅值、速度幅值和位移幅值；找到了横梁振动加剧的原因——共振；在此基础上建立了符合实际情况的横梁有限元模型，对模型进行了模态和谐响应计算，证实了模型的可靠性，为下一步的改进设计提供了依据。

Therefore, established a finite element Stable response model of a horizontal whole string and carried out t the safety varied frequency of gas well after researched the natural seriously transversal vibration and compressional vibration frequency range of tubing string with packer and packerless, so that it make the tubing string to avert the covibration frequency range of natural gas excited.

本文认为以某井高产量稳产时，天然气对油管柱的外激励为简谐激振，因此研究中建立某水平井全井段油管柱稳态响应的有限元力学模型，并获得了在无封隔器和有封隔器情况下的油管柱发生严重横振和纵振的频率范围，提出了天然气安全调节频率范围，使油管柱避开可能引起严重破坏的天然气激励频率区域。

Liu JunHua;Huang ShuGong;Liu JiDongA tri-dimensional model for a jeffcot rotor was reported. A new motion equation of the torsional vibration with natural retation and the conception frequency was presented. The natural frequencies of disk rotors with different geometrical structures and were computed based on the finite-element method, and the factors affecting the coefficient of the natural frequency with rotation were analyzed.

在转轴以一定速度旋转的条件下，推导了考虑转动频率情况下的单质量盘转子扭振运动方程，通过有限元方法对不同几何结构的单质量盘转子在不同转动频率下的扭振固有频率进行了计算，对影响单质量盘转子扭振动频的动频系数进行了分析。

The method is as follows that the two ends of a nanometer are fixed on two pivots and an axial micro-pulling force T is applied on the nanometer; an electrode is arranged on the middle part of the side of the nanometer and an alternate voltage is applied on the electrode to motivate the nanometer to generate resonance, and therefore, the natural frequency f of the nanometer is measured and acquired; according to the material characteristics and the geometry characteristics of the nanometer as well as the boundary condition of the nanometer material, the relation between the natural frequency and the axial pulling force of the nanometer, namely the f-t curves of the nanometer, can be calculated by a vibration equation; according to the measured natural frequency f, the size of the micro-pulling force T can be acquired.

该方法将一根纳米材料的两端固定在两个支点上，给纳米材料施加一个轴向的微小拉力T；在纳米材料的侧面，位于该纳米材料的中部放置一个电极，在电极上施加一个交变的电压激励纳米材料使其发生共振，测得纳米材料的固有频率f；根据纳米材料的材料特性和几何特征以及纳米材料的边界条件，由振动方程计算出该纳米材料的固有频率与所受的轴向拉力的关系，即纳米材料的f-T曲线；根据上述测得的固有频率f，得到微小拉力T的大小。

The formula put together the natural frequency f s of shearing bending vibration of superstructure rigidly fixed on the hull and the natural frequency f r of rigid rotating vibration of superstructure elastically fixed on the hull, in which t...

推导中 ，仍将上层建筑整体纵向固有频率视为由下述两部分串联合成：上层建筑根部刚性固定在主船体上的剪弯振动固有频率 fs；上层建筑根部弹性固定在主船体上的刚体转动固有频率 fr。

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