接触网零件振动试验方法探讨

通过对接触网零件用紧固件的耐振动性能进行振后扭矩测试和横向振动采用压力环测试应变进行对比分析，提出了合理的接触网零件耐振动性能试验方法。     

Robustness analysis of responses of vibration control structures with uncertain parameters using interval algorithm

Variations in system parameters due to uncertainties may result in system performance deterioration. Uncertainties in modeling of structures are often considered to ensure that control system is robust with respect to response errors. Hence, the uncertain concept plays an important role in vibration control of the engineering structures. The paper discusses the robustness of responses of vibration control systems with the uncertain parameters. The vibration control problem of an uncertain system is approximated by a deterministic one. The uncertain parameters are described by interval variables. The uncertain state matrix is constructed directly using system physical parameters and avoided to use bounds in Euclidean norm. The feedback gain matrix is determined based on the deterministic systems, and then it is applied to the actual uncertain systems. A method to calculate the upper and lower bounds of responses of the closed-loop system with uncertain parameters is presented. The upper bounds of responses can be used to estimate the robustness of responses of the controlled system with uncertain parameters. Two numerical examples are given to illustrate the applications of the present approach.     

Control of Wind-Induced Self-Excited Oscillations by Transfer of Internal Energy to Higher Modes of Vibration. II: Application to Taut Cables

In Part I of this paper, a theoretical basis is presented using a two-degrees-of-freedom model. In this second part of the study, the passive control and the two types of semiactive controls introduced in Part I are examined numerically for a taut cable experiencing wind-induced galloping motion. The passive and the semiactive control schemes for taut cables show a good similarity with the results obtained for the two-degrees-of-freedom model. The potential of using these control schemes in practical applications to flexible structures is demonstrated.     

Vibration control of a flexible structure using a hybrid mount

This paper presents vibration control of a flexible beam structure using a hybrid mount which consists of elastic rubber and piezoelectric stack actuator. After identifying stiffness and damping properties of the rubber and piezoelectric elements, a mechanical model of the hybrid mount is established. The mount model is then incorporated with the beam structure, and the governing equation of motion is obtained in a state space. A sliding mode controller is designed in order to actively attenuate the vibration of the beam structure subjected to high-frequency and small magnitude excitations. The controller is experimentally realized and measured control responses such as acceleration of the beam structure and force transmission through the hybrid mount are evaluated and presented in both frequency and time domains.     

主动约束层阻尼板结构动力学建模研究

将有限元法和GHM法相结合，给出了建立主动约束层阻尼（ACLD）板结构动力学模型的新方法。建模时，考虑到粘弹材料（VEM）的纵向位移影响，采用GHM方法描述VEM的本构关系，解决了VEM的力学特性随温度和频率变化的难点，避免因VEM的复杂本构关系而产生的微分积分方程。算例表明本文给出的建模方法是准确的，ACLD结构能够有效控制结构振动。     

高水头船闸输水廊道反弧门水弹性振动试验研究

本文简要介绍水弹性振动模型试验的相似准则，用近似满足水弹性相似准则的有机玻璃模型对－高水头船闸反弧形阀门进行流激振动试验研究．试验表明阀门的振动是随机振动，不仅有质量振动而且有结构振动，有若干阶模态被激发参与振动。在开门和关门过程中，阀门面板脉动压力和阀门振动是不大的，与葛洲坝船闸类似阀门间歇开启的振动水平相当。由于常压模型不能正确模拟空化现象，对于廊道内可能产生的空泡溃灭所引起的阀门振动尚需通过减压模型进行研究。     

用数采器对空压机进行状态监测预报

通过几个典型事例的分析、判断和处理，介绍了该厂怎样利用９１ｌ型数采器对２Ｄ１２—１００／８型空压机运行状态进行监测，以预报早期故障，为设备检修提供指导．     

高速铣削的非线性建模

当铣削速度提高到常规速度的5～10倍后,铣削过程将变得十分复杂.为此从动力学出发,利用切削理论和数值方法,建立了一个高速铣削的非线性动力学模型.其铣削力模型包括了铣刀的几何特征、铣削力和动态铣削力计算,以及系统动力学方程.并利用吉尔数值法编写了求解程序,程序具有自动变阶和调整步长的特点.利用该模型,可对铣削过程的特征参数如稳定性、切削力等进行预测.     

运输包装件振动特性的计算机仿真

应用有限元法对计算机主机在运输过程中的振动特性进行了计算机仿真。首先利用Pro/E建立几何模型，然后基于ANSYS进行有限元动力分析，求出了包装件的固有频率与固有振型，以及频域／时域的动态响应。     

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油管柱作为油气生产中的重要工具，它的使用寿命一直是工程技术人员关注的焦点。文章从动力学中固液耦合振动的角度出发，研究了油管柱内流体不稳定流动引起的油管柱振动问题。考虑液动压力对油管柱纵向振动的影响，建立了油管柱纵向振动微分方程，并给出了这种情况下油管柱纵向振动的频率方程。通过大天池构造上一口高压气井的实例计算分析，指出井内流体不稳定流动时，油管柱会产生相当高的附加动载。这个动载是造成油管柱在生产过程中发生疲劳破坏的主要原因之一，在今后的油管柱设计中应考虑这一动载的影响