双非线性动力减振系统的综合

该文继承R.E.Roberson关于非线性减振弹簧扩展系统抑制带的研究结果,进一步考虑采用非线性主弹簧改善系统性能的可能性,揭示主弹簧的非线性特性可使系统抑制带显著扩大.通过求解双非线性受迫振动方程,制定了这种情况下系统优化设计的原则.     

空气弹簧半主动式动力吸振器的研究

设计了一种应用于汽车发动机上的基于空气弹簧的动力吸振器.通过对空气弹簧和吸振器的研究,建立了以空气弹簧为弹性元件的半主动动力吸振器模型.并使用AMESim与MATLAB/Simulink联合仿真对动力吸振器系统进行仿真.     

带动力吸振器的空气主动悬架的仿真研究

针对空气主动悬架在高频段的振动问题,设计一动力吸振器,建立带动力吸振器的空气主动悬架的1/4车辆动力学模型,结合最优控制相关理论,对带动力吸振器的空气主动悬架控制器进行设计。运用Matlab编程功能对动力吸振器参数进行优化并得到了最优参数。应用Matlab/Simulink软件对带动力吸振器的空气主动悬架的动力学模型进行频域和时域的仿真研究,并与不带动力吸振器的主被动空气悬架进行对比分析。结果表明带有动力吸振器的空气主动悬架在高频段的减振性能明显优于被动空气悬架和常规空气主动悬架。     

A tunable dynamic vibration absorber for unbalanced rotor system

A tunable dynamic vibration absorber for unbalanced rotor system which is made up of coil springs and magnetic spring is presented. The structure of the absorber is introduced and the stiffness tuning mechanism of the magnetic spring is explained. A finite element model of the rotor-absorber system was built and the influencing factors to the appearance of the absorber were studied numerically. Finally, experiments were carried out to verify the numerical results, and PID control strategy was tested. The numerical and experimental results show that the present absorber is effective for vibration suppression of an unbalanced rotor system, and the control strategy is effective.     

硅油-橡胶复合阻尼式扭转减振器的设计方法及实验分析

降低发动机扭转振动的方法之一是加装曲轴扭转减振器。而传统的纯橡胶阻尼式曲轴扭转减振器由于其橡胶材料的滞后角普遍较小,因此不能在较宽的频域范围内提供适当的阻尼,导致其减振、隔振的效果较差。介绍了硅油-橡胶复合阻尼式扭转减振器的结构,建立了该扭转减振器的力学模型并提出了基于粒子群优化方法的设计参数优化方法。计算结果表明,优化后的系统中曲轴的扭转振动幅值降低,并通过实验验证了硅油-橡胶复合阻尼式扭转减振器控制发动机曲轴扭转振动的有效性。     

基于ANSYS的低频弹簧橡胶减振器结构设计

在某型号的电子设备的减振器设计中,综合考虑了振动、冲击两种主要的力学环境,以减振器刚度为设计变量,根据振动、冲击环境设计要求确定了约束条件,在ANSYS中建立了减振器的力学模型,分析确定了减振器的三个方向的弹簧常数.由于该电子设备需要从20Hz处的超低频开始减振,目前国内小型减振器的减振都不能达到这样的效果,因此该设计也是一种探讨研究.众所周知,弹簧减振器具有很好的低频特性,但是它没有适当的阻尼不能很好地抑制共振峰;而橡胶减振器有大阻尼特性,不足之处是它的低频减振效果不尽人意.为了兼顾弹簧的低颇特性和橡胶的阻尼特性,从弹簧和橡肢如何细合成低频减振器进行了理论研究,在设计过程以实验进行验证、指导,可为该类减振器的设计提供借鉴.     

On the use of damped updated FE model for dynamic design

Model updating techniques are used to update the finite element model of a structure, so that updated model predicts the dynamics of a structure more accurately. The application of such an updated model in dynamic design demands that it also predicts the effects of structural modifications with a reasonable accuracy. Most of the model updating techniques neglect damping and so these updated models cannot be used for predicting amplitudes of vibration at resonance and antiresonance frequencies. This paper deals with updating of the finite element model using the FRF data with damping identification using complex modal data and its subsequent use for predicting the effects of structure modifications. The updated model is obtained in two steps. In the first step, mass and stiffness matrices are updated using FRF-based model updating method. In the second step, damping is identified using updated mass and stiffness matrices, which are obtained in first step. Structural modifications in terms of mass and beam modifications are then introduced to evaluate the updated model for its usefulness in dynamic design.     

动力减振镗杆的减振性能研究

论述动力减振镗杆的工作原理,通过简化动力学模型建立微分方程.在理论基础上通过实验分析动力减振镗杆的减振效果和动态性能,并测定其最佳状态下的性能参数.试验结果确定了动力减振器的减振特点,为实际生产加工给出参考.     

Effect of a dynamic absorber on friction-induced vibration of a rectangular plate

When a plate-like object is rubbed by rubber, friction-induced vibration is generated. To reduce the friction-induced vibration, we experimentally investigate the characteristics of the vibration of a rectangular glass plate. The results show that the frequency of the friction-induced vibration is almost the same as the natural frequency of a glass plate. The vibration is generated when the natural frequency of a rubbing system is close to that of a glass plate. We then examine the effect of a dynamic absorber mounted on the glass plate. The results demonstrate that the damping of a dynamic absorber is effective for suppressing the friction-induced vibration. Numerical simulation is also performed using a simplified analytical model. The calculated results agree qualitatively with the experimental ones.     

夹层阻尼结构抑振特性研究

利用等效复合刚度法,对多夹层阻尼结构的抑振特性进行了理论推导,并对不同夹层阻尼结构的等效复合刚度和损耗因子进行了仿真计算,分析了不同的夹层材料和几何参数对结构抑振量的影响。研究表明,增加多夹层组合结构的夹层层数对组合结构损耗因子的提高量有限;适当增加夹层的厚度可改善组合结构抑振性能;变化夹层的材料,采用较硬的约束层和较软的阻尼层可显著提高组合结构的抑振量。     

基于遗传算法的两级隔振系统消振器参数优化研究

通过分析两级无源隔振系统设计中存在的问题,提出在第一级隔振质量块上安装第三质量-弹簧-阻尼系统作为隔振系统的消振器,由其抑制隔振系统的二阶模态,同时保证系统在高频区段的良好隔振性能.运用遗传算法对消振器各参数进行优化.对优化结果的仿真分析及试验研究表明:该方法切实可行,改善了系统的隔振性能.     

Computer-aided design on a perforated single-layer absorber under space constraints

As investigated by the Occupational Safety and Health Act (OSHA) in 1970, noise is highly responsible for the psychological and physiological illnesses of workers. Therefore, noise control for an enclosed manufacturing system using sound absorbers becomes indispensable. Considering the minimal acoustic wool used in the high-performance sound absorber during design optimization, the ratio of the sound absorption coefficient to the thickness of acoustic wool, a cost- and performance-oriented design index, is then applied and served as a researched objective accordingly; what’s more, the thickness of the absorber is fixed in advance for the sake of maintenance and access. In this paper, not only is the graphic analysis studied, but also, the computer-aided numerical assessments are presented. In the computer-graphic analysis on sensitivity, one set of design data is developed first. Additionally, the successive algorithm of iteration techniques and the original design data are carried out independently. Moreover, the results are then confirmed by the Kuhn-Tucker condition for accuracy purposes. It is shown that the theoretical and simulated results are in good agreement. The economical design of the sound absorber proposed in this study definitely provides a quick and optimal approach to minimize the amount of acoustic wool used and retain the higher acoustic performance of perforated single-layer absorbers under space restrictions.     

Optimum design of dynamic absorber for a random-excited machine mounted on a platelike structure foundation

The optimum design of a dynamic absorber for a machine mounted on a floor system is presented. The floor is considered to be a platelike structure. The transfer function is derived in closed-form. Based on the band-limited white-noise excitation, the optimum tuning and damping ratios of the absorber are determined by minimising the variance of response of the machine. Since the variance cannot be calculated directly by integrating the transfer function over the band-limited frequency range, the steepest descent method is used for determining these optimum parameters by iteration. The same procedure can be extended to deal with the cases of other multi degrees-of-freedom systems. The effects of mass ratios (i.e. absorber/machine and machine/floor), primary damping, frequency ratio and the thickness of plate on the design parameters are examined. The results show that the values of optimum tuning are much different from those of the rigid foundation case. To have a small variance, it is better to keep the frequency ratio ω₁ (defined as the frequency of primary system divided by half of the lowest natural frequency of the floor) in the range 1 < ω₁ < 1.5, and have the mass ratio μ and the primary damping ratio ζ₁ are both greater than 0.1.     

Vibration control of the axisymmetric spherical pendulum by dynamic vibration absorber moving in radial direction

In the current paper, a dynamic vibration absorber (DVA) is proposed to suppress the vibration of the axisymmetric spherical pendulum. The proposed DVA can reduce the bi-directional vibration of the pendulum by one mass, which moves in the radial direction (up and down). The global stability of the system is analyzed using the Lyapunov function. The proposed DVA is proven effective, especially for the suppression of large vibration. The DVA natural frequency should be tuned to twice as that of the axisymmetric spherical pendulum. The effectiveness of the proposed DVA is demonstrated through an example of liquid sloshing reduction in a cylindrical tank.     

基于ADMAS/CAR仿真的汽车减振系统的设计

麦弗逊式独立悬架因结构简单等优点作为汽车减振系统被广泛应用于微型车与轿车前悬。通过对汽车减振系统——麦弗逊式独立悬架进行设计,利用UG软件建模并进行测量而获取各硬点数据,并利用ADAMS软件建立1/2车辆模型对汽车悬架进行动态仿真,从而验证设计的正确性,达到优化设计的目的。     

振动攻丝扭矩动态信号的研究

用快速傅里叶变换方法针对振动攻丝扭矩测量信号进行频谱分析,并采用数字信号滤波技术对各组成信号进行提取.信号分析结果表明:测量信号中主要包括扭矩信号及径向跳动信号;扭矩信号的频率与外加振动频率相一致,径向跳动信号随攻丝过程的持续进行逐渐变大.攻丝扭矩信号分析为振动参数对振动功丝扭矩影响规律的研究提供依据.     

多维减振平台控制系统的研究

综述了多维减振平台控制系统的基本类型及其特点,并介绍了它们的发展概况.重点论述了半主动控制减振平台的几种控制方法,对今后的研究方向和发展趋势进行了初步的探讨.     

Analysis of the dynamics of a pendulum vibration absorber

The nonlinear dynamics of an autoparametric vibration absorber of pendulum type is considered. The conditions of existence of periodic motions in the case of monoharmonic excitation are considered. A comparison of the vibration quenching qualities of the autoparametric absorber and a “classical” (linear) dynamic vibration absorber is presented.     

基于仿真的机构动平衡实验台振动研究

将机械动力学与有限元分析方法相结合,建立了机构动平衡实验台振动测量的仿真方法.通过将轴承座设为柔体,对比分析了平面四杆机构平衡前后的振动情况.通过仿真计算,有利于在设计阶段掌握机构的平衡程度,该方法对同类复杂机构的动平衡分析具有参考价值.