双调节挤压式磁流变减振器特性研究

为了解决挤压式磁流变减振器大阻尼小位移这一特性不适用于车辆的不足,设计外部滚珠丝杠结构,建立运动学、动力学模型,理论计算和仿真分析减振器外部连杆运动速度、位移和磁流变液剪切屈服强度对阻尼力的影响。对该减振器的示功特性和连杆长度比对阻尼力的调节作用进行了分析,最后进行了台架实验。实验得到该减振器不同电流下的示功图,和理论分析的结果基本一致,说明该阻尼力表达式正确,滚珠丝杠结构可以增大挤压式减振器位移和阻尼力的调节范围,使之适用于车辆,并使其具备机械电磁双调节模式。     

挤压式磁流变减振器力学模型研究

为了克服剪切阀式磁流变减振器阻尼力最大值不够的缺陷,建立了挤压式磁流变减振器的数学模型,得出了挤压式磁流变减振器的阻尼力表达式,并定义了等效阻尼系数和可调倍数.根据理论推导的表达式,分析了磁流变液在平行圆盘间的流动特性以及影响阻尼力的因素.分析结果从理论上证明挤压式磁流变减振器是小位移大阻尼减振器,位移3mm情况下,最大阻尼力和可调倍数分别可达5 000N和9.794 7.     

常温条件下双筒液压减振器动态特性的试验研究

为评价新开发的某型号双筒液压减振器的动态特性,运用MTS减振器综合性能测试示功机对其进行动态特性试验,得到其位移特性和速度特性曲线。结果表明,位移特性曲线可以反映该减振器阻尼力特性,速度特性曲线可以反映该减振器速度特性。基于位移特性曲线和减振器速度特性曲线评价常温20℃下该减振器的动态性能,结果表明,当减振器运行到1/4周期时,阻尼力和活塞杆速度达到复原过程最大值,而位移处于减振器的中心位置;减振器运行到2/4周期时,阻尼力和活塞杆速度值接近于0,而位移达到最大值50 mm;减振器运行到3/4周期时,阻尼力和活塞杆速度达到压缩过程最大值,而位移处于减振器的中心位置;当减振器运行完一个周期时,阻尼力和活塞杆速度值接近于0,而位移达到最小值-50 mm。研究表明,该型号减振器动态特性比较稳定,但在路面有较大冲击情况下位移会超出其工作行程±50 mm,因此应增加减振器工作行程以适应复杂的路面工况。     

一种小位移大阻尼力磁流变阻尼器的设计与研究

根据小位移大阻尼力的减振要求,提出了一种挤压式磁流变阻尼器的设计方案,并基于ANSYS进行了磁路的仿真,证明设计的方案是可行的.测试表明:随着电流的增加,减振器示功图曲线包围面积逐渐增大,耗能增加,减振效果增强,阻尼力可以实现连续调节.由速度-力图知阻尼特性表现为非牛顿流体特性,具有非线性滞回特性.     

磁流体行为指数对磁流变冲击阻尼器性能的影响

根据应用于火炮的冲击型磁流变(MR)阻尼器的特点,基于Herschel-Bu lkley本构模型,建立了某25 mm火炮磁流变后坐阻尼器的平行板一维层流模型,获得了不同磁场作用下阻尼力随活塞速度的变化规律。根据某单管25 mm火炮的后坐运动方程,计算了不同MR流体行为指数下,火炮的后坐位移和后坐速度,评价了MR流体行为指数对后坐阻尼器行为的影响。     

可回收振动能量的新型汽车减振器设计与仿真

为回收汽车行驶过程中的振动能量,设计了一种机-电-液混合的液电馈能式汽车减振器。通过由单向阀组构成的液压桥路,将减振器内的往复液压流整合为单向液压流。单向液压流驱动马达工作,从而带动发电机发电;同时,利用发电机反电动势的阻力实现减振器的阻尼力效果。依据功率平衡和转矩平衡原理,建立了减振器压缩行程和伸张行程的阻尼力动力学模型。通过对示功特性及速度特性的仿真分析,验证了回馈振动能量的可行性。     

汽车液压减振器设计研究

阐述了可调阻尼液压减振器的设计方案,对可调阻尼减振器性能进行了理论分析,针对减振器拉伸和压缩阶段各进行了力-速度特性计算,推导出数学关系式,在原车被动液压减振器的基础上,改进设计了一种节流口式可调阻尼液压减振器,并对此进行了台架试验。试验结果表明:所研制的可调阻尼液压减振器阻尼力与步进电机转角成对应关系,符合设计和使用要求。     

建模与仿真技术在汽车减振器压缩行程过程中的应用

汽车液力式减振器的关键参数是其阻尼力的相应速度。然而,传统的静态设计是确定系统经过瞬间响应达到稳定状态时的参数。以捷达汽车前左减振器为模型,对其压缩行程中活塞杆运动速度、阻尼力等对于时间和位移的函数进行了建模分析和数字仿真,这为设计提供了依据。为使减振器对车辆动态响应加快,选欠阻尼参数。     

汽车磁流变减振器的设计及多项式模型的研究

通过对汽车磁流变减振器的工作模式的分析,利用ANSYS电磁场模块和流体动力学模块,建立减振器磁路有限元模型。采用序惯耦合法,计算得出阻尼力-速度关系曲线,完成了汽车磁流变减振器结构优化设计及磁路分析。将所设计的磁流变减振器在MTS849减振器试验台上进行试验,测得磁流变减振器的示功图和速度特性,利用试验数据,进行多项式拟合,精确的建立了该减振器的阻尼力模型,与理论计算曲线比较,说明多项式模型能较好的描述减振器非线性特性和滞回特性。     

磁流变减振器建模与试验

建立较为精确的磁流变减振器阻尼力模型是设计控制策略并获得良好控制效果的关键。基于流体动力学理论和磁流变液流变特性,对阻尼通道内磁流变液进行流体动力学分析,详细推导磁流变减振器阻尼力模型。结合阻尼通道处磁场有限元分析,完善阻尼力模型。最后试验测试自制磁流变减振器在不同励磁电流和不同活塞速度下的示功特性和速度特性,利用试验数据对模型进行系数辨识,建立磁流变减振器简化力学模型。研究结果表明,励磁电流小于0.8 A时,输出阻尼力试验值与计算值较吻合,当励磁电流增大,阻尼力试验值与计算值最大相差约100 N,计算值相对于试验值的误差在19%以内,该简化力学模型能描述磁流变减振器的基本力学特性,能为半主动悬架控制研究提供理论指导。     

自适应隔离器系统抗冲击特性研究

基于将传统减振元件与智能元件并联的思想,应用现有减振元件钢丝绳弹簧和智能出力元件磁流变阻尼器设计动力学特性智能可控的自适应隔离器,可以同时解决中低频减振和高频抗冲击的问题.对该系统竖直方向上的抗冲击特性进行数值仿真和物理实验研究; 结果表明,自适应隔离器系统具有良好的抗冲击特性,尤其是在冲击载荷较强,系统会发生二次碰撞时,系统的抗冲击效果明显优于传统减振元件.     

小位移挤压式磁流变阻尼器的实验研究

设计了小位移、大阻尼力特性的挤压式磁流变阻尼器,并进行了相应的实验研究,包括示功特性和阻尼特性,以及所选用的重庆仪表材料研究所磁流变液MRF-01K的饱和磁场强度.实验结果表明,随着电流的增加,减振器示功图曲线包围面积逐渐增大,耗能增加,减振效果增强,其与激振器的激振频率关系不大;由阻尼特性曲线可知,阻尼器的输出力既与阻尼器电流有关,又与激振器频率有关,频率越大,电流越大,输出的力越大.     

磁流变阻尼器阻尼性能研究

为了研究新型可控流体磁流变液的特性以及利用以磁流变液为流体的阻尼器的阻尼特性，本文对磁流变液的重要组成部分——磁性微颗粒进行了介绍．并讨论了描述磁流变液的流变模型。在分析现有磁流变阻尼器结构的基础上．提出了一种改进的阻尼器结构。最后对改进结构测试了其性能，分析了影响其性能的各种因素，并提出了目前尚待解决的主要问题。     

Optimal design of Magneto-Rheological damper comparing different configurations by finite element analysis

Magnetorheological (MR) damper is one of the most advanced applications of semi active damper in controlling vibration. Due to its continuous controllability in both on and off state its practice is increasing day by day in the vehicle suspension system. MR damper’s damping force can be controlled by changing the viscosity of its internal magnetorheological fluids (MRF). But still there are some problems with this damper such as MR fluid’s sedimentation, optimal design configuration considering all components of the damper. In this paper both 2-D Axisymmetric and 3-D model of MR Damper is built and finite element analysis is done for design optimization. Different configurations of MR damper piston, MR fluid gap, air gap and Dampers housing are simulated for comparing the Dampers performance variation. From the analytical results it is observed that among different configurations single coil MR damper with linear plastic air gap, top and bottom chamfered piston end and medium MR fluid gap shows better performance than other configurations by maintaining the same input current and piston velocity. Further an experimental analysis is performed by using RD-8041-1 MR Damper. These results are compared with the optimized MR Damper’s simulation results, which are clearly validating the simulated results.     

汽车悬架磁流变减振器的优化设计及仿真

基于磁流变减振器在汽车悬架减振系统半主动控制中的广泛应用,根据磁流变液的特点和磁流变减振器阻尼力与结构参数的关系,设计了新型的磁流变减振器,并对影响磁流变减振器性能的参数进行了优化和仿真.仿真计算表明,该磁流变减振器设计是一种能优化阻尼力的有效算法.     

Variable stiffness and damping magnetorheological isolator

This paper presents the development and characterization of a magnetorheological (MR) fluid-based variable stiffness and damping isolator. The prototype of the MR fluid isolator is fabricated, and its dynamic behavior is measured under various applied magnetic fields. The parameters of the model under various magnetic fields are identified, and the dynamic performance of the isolator is evaluated in simulation. Experimental results indicate that both the stiffness and damping capability of the developed MR isolator can be controlled by an external magnetic field.     

磁流变阻尼器优化设计与性能分析

利用磁流变液这种智能材料的力学性能 ,制作了一种双出杆磁流变阻尼器。文中主要讨论了磁流变阻尼器结构设计、磁路设计的基本原理 ,并讨论了结构参数对磁流变阻尼器性能的影响 ,最后优化设计了磁流变阻尼器的结构参数 ,给出了磁流变阻尼器结构参数的匹配关系     

Finite Difference Solution of Response Time Delay of Magneto-rhelological Damper

Magneto-rhelological(MR) dampers are devices that employ rheological fluids to modify their mechanical properties. Their mechanical simplicity, high dynamic range, lower power requirements, large force capacity, robustness and safe manner of operation in cases of failure have made them attractive devices for semi-active real-time control in civil, aerospace and automotive applications. Time response characteristic is one of the most important technical performances of MR dampers, and response time directly affects the control frequency, application range and the actual effect of MR dampers. In this study, one kind of finite difference solution for predicting the response time of magneto-rheological dampers from "off-state" to "on-state" is put forward. A laminar flow model is used to describe the flow in the MR valve, and a bi-viscous fluid flow model is utilized to describe the relationship of shear stress and shear rate of MR fluid. An explicit difference format is used to discretize the Novior-Stoks equation, and stability condition of this algorithm is built by Von-Neumann stability criterion. The pressure gradient along the flow duct is solved by a dichotomy algorithm with iteration, and the changing curve of the damping force versus time of MR damper is obtained as well. According to the abovementioned numerical algorithm, the damping forces versus time curves from "off-state" to "on-state" of a cylindrical piston type MR damper are computed. Moreover, the MR damper is installed in a material test system(MTS), the magnetic field in the wire circles of the MR damper is "triggered" when the MR damper is imposed to do a constant speed motion, and the damping force curves are recorded. The comparison between numerical results and experimental results indicates that this finite difference algorithm can be used to estimate the response time delay of MR dampers.     

Vibration control of a structure using Magneto-Rheological grease damper

This paper describes an application study of Magneto-Rheological (MR) grease damper to a structure with three stories. MR fluid is known as one of successful smart materials whose rheological properties can be varied by magnetic field strength, and has been applied to various kinds of device such as dampers, clutches, engine mounts, etc. However, ferromagnetic particles dispersed in MR fluid settle out of the suspension after a certain interval due to the density difference between the particles and their career fluid. To overcome this defect, we have developed a new type of controllable working fluid using grease as the career of magnetic particles. Network of thickener in grease is expected to hold the magnetic particles and prevent them from settled down. No or little sedimentation was observed in MR grease whose characteristics could be controlled by the magnetic field strength. MR grease was introduced into a cylindrical damper and its performance was studied. As a result, it was confirmed that the damping force of MR grease damper could be controlled by the applied electric current to the coil in the cylinder of damper. Furthermore, vibration response of a three-story model structure equipped with MR grease damper was investigated experimentally, and it was shown that MR grease damper worked effectively as a semi-active damper.     

冲击载荷作用下磁流变阻尼器的建模与分析

以某12．7 mm机枪的磁流变(MR)后坐阻尼器为研究对象,基于Herschel-Bulkley本构模型,建立了该MR后坐阻尼器的轴对称一维层流模型。运用ANSYS软件,对该阻尼器的MR阀进行了磁场有限元分析,求得了环状间隙间MR流体的磁通密度。将MR流体流动模型和MR阀有限元结果相结合,建立了不同磁场作用下阻尼力随活塞速度的变化规律,利用这些规律对该阻尼器的落锤撞击试验和实弹射击试验进行了数值仿真。理论与试验结果的对比指出,在低磁场作用的情况下,理论与试验结果具有较好的一致性。