某型机液压阻尼器设计计算

液压阻尼器是某型机旋翼研制中的关键元件。本文根据直8液压减摆器性能试验结果拟合出直8型机液压阻尼器力—速度曲线,获得直8型机液压阻尼器定压活门开启速度;采用数值仿真方法对直8液压阻尼器和某型机液压阻尼器轴向速度进行了计算;采用薄壁小孔等效阻尼系数计算公式对直8液压阻尼器和某型机液压阻尼器节流片节流孔面积进行了计算;同时进行了某型机液压阻尼器补油装置油液体积的计算。上述计算方法和计算结果可为某型机液压阻尼器结构设计提供依据。     

新型磁流变减摆器节流孔流场分析

节流孔是磁流变减摆器产生阻尼的主要方式,在磁流变减摆器实际工作环境下,磁流变液经过磁场时会随磁场分布强度不同而产生变黏度等应激变化。建立某新型磁流变减摆器计算模型,通过改变节流孔孔径大小,使用商业软件 Fluent 对其所产生的流场进行分析,将模拟结果与实验结果进行对比。结果表明:磁流变液流通量及淤积效应是决定磁流变减摆器初始阻尼及时滞效应的主要原因;在 0.2mm 孔径时时滞效应最明显,且随频率增高磁流变减摆器对于外界激励反应速度明显下降。     

带缘板阻尼块涡轮叶片减振特性研究

以某型带缘板阻尼块涡轮叶片为对象,采用二维整体-局部统一滑动模型,编制涡轮叶片振动响应分析程序。在此基础上系统地计算不同参数时带缘板阻尼块叶片的振动响应,分析了正压力、外激励对减振效果的影响。算例分析表明:同一外激励下,存在一最佳正压力可以使系统减振效果比较好;正压力不变时,外激励幅值大小的变化对叶片减振效果有较大影响;另外阻尼块对叶片起到调频作用。     

带弹支干摩擦阻尼器的转子振动控制 策略和方法

根据弹支干摩擦阻尼器的特点,提出弹支干摩擦阻尼器控制转子振动的方案,建立了基于主动弹支干摩擦阻尼器的比例积分控制(PI控制)和连续增益调度比例积分控制(连续GSPI控制)方法,对两种控制方法控制转子通过临界转速的振动进行了理论分析、数值仿真和试验验证,并分析了其特点.      

Nonlinear vibration response characteristics of a dual-rotor-bearing system with squeeze film damper

Rolling bearing and Squeeze Film Damper (SFD) are used in rotor support structures, and most researches on the nonlinear rotor-bearing system are focused on the simple rotor-bearing systems. This work emphasizes the comparative analysis of the influence of SFD on the nonlinear dynamic behavior of the dual-rotor system supported by rolling bearings. Firstly, a reduced dynamic model is established by combining the Finite Element (FE) method and the free-interface method of component mode synthesis. The proposed model is verified by comparing the natural characteristics obtained from an FE model with those from the experiment. Then, the steady-state vibration responses of the system with or without SFD are solved by the numerical integration method. The influences of the ball bearing clearance, unbalance, centralizing spring stiffness and oil film clearance of SFD on the nonlinear steady-state vibration responses of the dual-rotor system are analyzed. Results show that SFD can effectively suppress the amplitude jump of the dual rotor system sustaining two rotors unbalance excitations. As the ball bearing clearance or unbalance increases, the amplitude jump phenomenon becomes more obvious, the resonance hysteresis phenomenon strengthens or weakens, the resonant peaks shift to the left or the right, respectively. SFD with unreasonable parameters will aggravate the system vibration, the smaller the oil film clearance, the better the damping performance of the SFD, the larger the centralizing spring stiffness is, the larger resonance amplitudes are.     

Ф5m立式风洞阻尼器的研制和应用

立式风洞开展自由失速/尾旋试验要求试验段气流速度具备快速调节能力,阻尼器是实现试验段气流速度快速调节能力的装置。叙述了阻尼器机械结构设计和它的功效,说明了控制系统设计及联调结果,介绍了试验段气流速度快速性调试方法及结论。系统应用表明,风洞试验段气流速度具备一定快速调节能力,具备开展自由失速/尾旋试验条件。     

某电子设备耐大量级振动组合式减振器研制

某电子设备在飞行过程中遭受均方根加速度高达38 g的振动环境,为了降低其振动响应,采用有限元分析和试验验证相结合的方法,研制了一种新型的组合式橡胶减振器。通过与T型减振器进行对比试验,结果表明,设计的组合式橡胶减振器使电子设备的随机振动响应由38 g下降到11 g,减振效率高达71%,且共振峰放大倍数小于3。     

直升机旋翼磁流变阻尼器样件仿真和试验验证

基于一种线圈内置剪切阀式磁流变阻尼器结构,设计了一种全尺寸旋翼磁流变阻尼器结构,并将结构参数与磁路参数进行关联,提出了一种基于活塞组件结构的磁路结构参数仿真优化方法.基于改进的Bingham模型,建立了该全尺寸旋翼磁流变阻尼器参数化阻尼功计算模型.研制了全尺寸旋翼磁流变阻尼器样件,开展了性能试验与试验验证技术研究,研究...     

主动式弹支干摩擦阻尼器控制转子振动的实验

设计了一种主动控制式弹支干摩擦阻尼器.实验研究了该主动控制式弹支干摩擦阻尼器对转子减振的效果.实验发现,通过选择合适的控制方案,主动式弹支干摩擦阻尼器能够对转子振动进行有效控制,减振效果明显.另外,实验表明,主动控制式弹支干摩擦阻尼器结构简单,易于施加控制,功耗小,将是一种很有应用前景的转子主动减振结构.      

Adaptive Control of Helicopter Ground Resonance with Magnetorheological Damper

The methodology for adaptive control of helicopter ground resonance with magnetorheological （MR） damper is presented. The adaptive inverse control method is used to control the output damping force of MR damper and the range of the damping force is given. Through the adaptive inverse control, the damping force of MR damper is fit to a desired damping force. With the background of applying MR damper to control of helicopter ground resonance, a model of loss force and an adaptive arithmetic for stabilization of the coupled rotor/fuselage system are presented. The simulation shows that the controller presented in this paper can stabilize the rotor/fuselage coupling system quickly and control the helicopter ground resonance effectively.