非线性振动

The motion of a type of nonlinear damped oscillation is analyzed to resort the method of numerical analysis, and compared it with the motion of the linear damped oscillation.

摘要用数值分析方法分析一类非线性阻尼振动问题，与线性阻尼振动进行比较，得到非线性阻尼振动状态每次过θ=0位置的时刻稍后于线性阻尼振动状态。

The motion of a type of nonlinear damped oscillation is analyzed to resort the method of numerical analysis,and compared it with the motion of the linear damped oscillation.

用数值分析方法分析一类非线性阻尼振动问题，与线性阻尼振动进行比较，得到非线性阻尼振动状态每次过θ=0位置的时刻稍后于线性阻尼振动状态。

The natural twist vibration equation is set up by making use of the constitutive relation of nonlinear material.

利用非线性材料的本构关系，建立了非线性材料圆杆的扭转固有振动方程，然后采用傅立叶级数法求得了圆杆扭转固有振动的所似解，通过实例计算讨论分析了非线性材料圆杆的扭转固有振动特性。

The free vibration of a nonlinear elastic rectangular plate is explored, considering influence of material nonlinearity and static-load in plane on its dynamic characteristics. Exact solution to free vibration of each mode of the rectangular plate is obtained according to the fixed point theory of partially ordered space. So the whole process of free vibration is described.

对非线性弹性矩形板的自由振动进行了研究，考虑了材料非线性和面内静载对板动力特性的影响，并根据半序空间的不动点理论求得该矩形板在自由振动时各阶模态的精确解，描绘了其自由振动的全过程。

Based on the generalized potential energy variational principle of nonlinear elasticity theory with large deflection,the incomplete generalized potential energy functional is established on the space coupling free vibration of three-span self-anchored suspension bridge by considering the effect of coupling of flexural and axial action,and shearing strain energy of stifening girder.

摘 要：基于大位移非线性弹性理论的广义变分厚理，考虑了加劲梁的压弯耦合和剪切应变能的影响，建立了三跨自锚式悬索桥空间耦合自由振动的大位移不完全广义势能泛函，通过约束变分导出了自锚式悬索桥的竖向挠曲振动、横向挠曲振动和纵向振动的基础微分方程，忽略非线性项的影响，进而得到线性振动微分方程。

Based on the generalized potential energy variational principal of nonlinear elasticity theory with large deflection, the incomplete generalized potential energy functional with large deflection is established on the space coupling free vibration of three-span self-anchored suspension bridge by considering the effect of axial compressive and shearing strain energy of stiffening girder.

摘 要：摘要：基于大位移非线性弹性理论的广义变分原理，考虑了加劲梁轴向压缩应变能和剪切应变能的影响，建立了三跨自锚式悬索桥空间耦合自由振动的大位移不完全广义势能泛函，通过约束变分导出了自锚式悬索桥的竖向挠曲振动、横向挠曲振动、纵向振动及扭转振动的基础微分方程，为自锚式悬索桥的固有振动性状分析提供可靠的理论依据。

The dynamic capability of the milling process is influenced by a lot of nonlinear factors. Considering the machine tools rigidity, time delay and uncontinuous cutting, etc, a nonlinear model to prodict the vibration is proposed in this paper.

因此，为了预报切削系统中振动的发生，本文考虑了机床刚度的非线性和铣削过程时延、断续切削等非线性因素，建立了一个预报铣削振动产生的非线性模型。

In this paper Ⅰ successfully applied these methods to fault diagnosis, and presenting some new innovative machinery fault diagnosis method; First Ⅰ present a new gear wornout fault diagnosis method, this method use the vibration signal's time-frequency attribute and instantaneous phase undulation to accurately detect gear's fault, and by comparing with the traditional frequency domain analysis method, this method reveals that many nonlinear and nonstationary characteristic exist in gear's vibration, this tell us that if we use frequency domain analysis method without pay attention to the signal's characteristic, we could get wrong diagnostic result; Then Ⅰ present a new bearing fault diagnosis method, this method use ATVFD and Hilbert transform to do envelop demodulation,Ⅰ analyze the envelop with time-frequency method and find out that this method is more accurate then traditional method.Ⅰ also explain that the modulation of the fault to the carrier wave may also be non-stationary and nonlinear; Finally Ⅰ present a cylinder pressure measurement method of diesel engine by means of vibration, cylinder pressure is an important parameter of diesel engine fault diagnosis, the pressure measuring is simplified a lot by this method,Ⅰ also use the ATVFD and time-frequency analysis to realize it.

本文中将上述理论方法成功地应用到故障诊断中去，提出了几点创新性的诊断方法；提出了一种齿轮磨损故障诊断的新方法，该方法利用振动信号能量的时频域分布特征与瞬时相位波动特征可以进行精确的齿轮故障诊断，并通过与传统的频域诊断方法的比较，揭示出齿轮振动中存在的明显的非线性与非平稳特征，说明了不加选择地利用频域分析方法进行齿轮故障诊断很可能会得到错误的诊断结果；提出了一种轴承故障诊断的新方法，该方法利用ATVFD分解与Hilbert变换进行包络解调，并对解调得到的包络信号进行时频域分析，可以实现更加准确轴承故障诊断，说明了故障对载波信号的调制往往也是非平稳与非线性的；提出了一种利用振动信号进行柴油机汽缸内压力检测的新方法，柴油机汽缸压力的变化是柴油机故障诊断的重要参数，利用振动方法可大大简化汽缸压力的检测过程，该方法也是综合利用ATVFD分解与时频域分析方法实现的。

First, the angular velocity function and maneuver load for certain maneuver flight (including hover, dive-hike and these two combined) are set up. The simulation results of the vibration of double-disk rotor system with cantilever supported on rigid bearings show that rotor would be apparently deformed under maneuver load. Second, the performance of oil force of SFD in maneuver flight is analyzed. The results show that in maneuver flight, the SFD with centering spring will become eccentric and its oil force will be time-related and offset-related.

首先，建立了水平盘旋、俯冲拉起及盘旋+俯冲拉起复合机动三种机动飞行条件下的机动角速度函数，并确定了对应机动飞行条件下的机动附加载荷（附加离心力和附加陀螺力矩），分析了带刚支的双盘悬臂转子系统在机动飞行条件下的振动特性，发现发动机转子在机动飞行时会发生明显变形；随后，分析了非定心挤压油膜阻尼器的油膜力特性，机动飞行时，油膜轴颈在机动附加载荷的作用下偏离外环中心，使得带定心弹支的挤压油膜阻尼器也变成了非定心挤压油膜阻尼器，其非定心挤压油膜力是瞬态时变的，并且与SFD油膜轴颈偏移量和进动形态有关；然后，在经典的Jeffcott转子系统中引入带定心弹支的挤压油膜阻尼器，分析了机动飞行时非线性转子系统的振动特性，发现挤压油膜阻尼器油膜力的非协调特性也反映到转子系统的振动响应中；之后，对机动飞行条件下带挤压油膜阻尼器的双盘悬臂转子系统的振动特性进行了分析，并重点分析、总结了俯冲拉起机动飞行时，系统结构参数和工作状态参数（转速比、机动飞行半径、机动角速度等）对该系统振动特性的影响。

Because the error mainly comes from theresonant region, the error correction method can only be used in resonant region, andcan effectively improve the efficiency of the statistical analyzing solutions. Two types of the mistuned bladed disks, whose friction damping are blade dryfriction damping and blade-to-blade dry friction damping, are modeled respectively. Amulti-harmonic method which can employ the fast Fourier transformationtechnique is proposed to investigate the vibratory response of the bladed disks withthese two types of nonlinear friction damping. Formulations of the solution for thesetwo types of motion functions are deduced. The characteristics of the forced responseof the bladed disks with these two dry friction damping are analyzed and summarizedunder various system parameters. The vibratory response of the bladed disk with dryfriction scatter mistuning is investigated.

针对叶盘系统中两类主要的非线性干摩擦阻尼形式，分别建立了具有叶片干摩擦阻尼和叶间干摩擦阻尼的失谐叶盘系统的非线性力学模型；提出了一种可利用快速傅立叶变换技术的多谐波分析方法；分别推导了具有这两类干摩擦阻尼形式的叶盘系统运动方程的求解公式；在各种系统参数条件下，研究了干摩擦阻尼失谐叶盘系统的受迫振动响应特性；对具有干摩擦散乱失谐的叶盘系统振动响应进行了研究，分析总结了干摩擦散乱失谐对叶盘系统振动响应特性的特殊影响规律。

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。