PVC/丁基再生胶磁性阻尼材料的制备与性能

为了制备宽温域、高阻尼、阻燃、易加工且性价比高的阻尼材料,以聚氯乙烯(PVC)作为塑料组分,以环保丁基再生胶作为橡胶组分,采用动态硫化的方法制备了 PVC/丁基再生胶热塑性弹性体阻尼材料。研究了 PVC 改性剂及磁粉等填料用量对热塑性弹性体性能的影响,并进行了力学性能、耐热性、阻燃性和阻尼等性能测试。结果表明,使用氯化聚乙烯(CPE)、氯化聚氯乙烯(CPVC)改性 PVC 时,CPE 的综合改性效果优于 CPVC。当 CPE 用量为20 份时,所制得的热塑性弹性体综合性能最优。当磁粉等填料用量为 120 份时,热塑性弹性体的综合性能最佳;动态热机械分析结果表明,在 55~100℃,热塑性弹性体的阻尼因子(tanδ)≥ 0.3,阻尼温域范围达到 155℃,阻尼性能良好,尤其是在 9℃左右 tanδ达到了 0.66,阻尼性能最佳。

IPN磁性阻尼板的制备及性能研究

本文介绍了磁性阻尼板的制备方法 ,并对其性能进行了研究。实验结果表明 :添加适量的磁粉既能增加阻尼板的磁通密度 ,又不会降低阻尼因子 ,制得的阻尼板能够很好地粘贴在金属表面上。

具有磁性阻尼功能的线性发电机的研发

介绍了日本使用零相电流控制、具有磁性阻尼功能的线性发电机的研发和试验概况。

铁铬钴磁性阻尼装置

本产品是对电度表中原有的阻尼永久磁铁装置的永磁体采用铁铬钴合金,是一项新材料应用专利技术,属国际首创,技术先进。 采用铁铬钴合金的磁性阻尼装置代替原铝镍钴五类磁钢,用于DD862型等各种电度表上,其材料为无镍、低钴、含钴量为12％,是原铝镍钴的含钴量的50％,可为国家解决钴资源的紧缺,给社会和企业带来较大效益。

采用磁流变（MR）阻尼器控制斜拉索振动

磁流变阻尼器是典型的可控流体器件。本文介绍了磁流变阻尼器的特性及仿真结果，重点介绍了彩磁流变阻尼器的实现斜拉索振动控制的可行性及具体控制方案，给出了六种不同民政部仿真结果。

阻尼式钢丝绳回转检测装置

针对钢丝绳生产中回转检测缺陷,设计一种阻尼式钢丝绳回转检测装置,防止钢丝绳扭力较小时回转检测轮产生偏转,提高钢丝绳产品质量。

MR damping design of the drive joints of the lunar-based extravehicular spacesuit booster mechanism

Considering the special walking behavior of astronauts on the lunar surface,to reduce the impact on their bones and improve safety during extravehicular operations and walking,a magnetorheological(MR)damping mechanism of power assisted transmission joint used in a new type spacesuit is proposed.In order to improve the damping performance of the MR damper,the influence of the damper s structural parameters on both the output and dynamic adjustable range of the damping torque is examined.According to the theoretical mechanical model,the output damping torque is calculated,the finite element method is used to conduct numerical tests.At the same time,the structural parameters of the damper are optimized by the response surface methods.The results indicate that the simulated torque aligns with the theoretically designed torque,and the damping characteristics of the optimized structure are effectively improved by the response surface method.Compared with the initial structure,the damping torque is increased by 10.8%,and the dynamic adjustable range is expanded by 52.9%.

Damping of Magnetorheological Elastomers

The damping property of magnetorheological （MR） elastomers is characterized by a modified dynamic mechanical-magnetic coupled analyzer. The influences of the external magnetic flux density, damping of the matrix, content of iron particles, dynamic strain, and driving frequency on the damping properties of MR elastomers were investigated experimentally. The experimental results indicate that the damping properties of MR elastomers greatly depend on the interfacial slipping between the inner particles and the matrix. Different from general composite materials, the interracial slipping in MR elastomers is affected by the external applied magnetic field.

Modeling and control of MR damper considering trapped air effect

Due to the high viscosity of magnetorheological(MR)fluid,eliminating air pockets dissolved in the fluid is very difficult,which results in a force lag phenomenon.In order to evaluate the performance of a semi-active control system based on the MR damper considering the trapped air effect,a performance test on a MR damper is carried out under different loading cases,and the influence of the input current,excitation amplitude and frequency on the force lag phenomenon is analyzed.A concise and efficient parametric model,combining the simple Bouc-Wen model and a spring with small stiffness,is proposed to portray the experimental characteristics of the MR damper with force lag,and then the response analysis of the semi-active controlled single-degree-of-freedom(SDOF)structure is performed using the classic clipped-optimal control strategy based on acceleration feedback.Numerical results show that the trapped air in the MR fluid can weaken the control effect of the MR damper,and the performance of the semi-active control system will be reduced more obviously and become close to the passive-off control with the increasing content of air trapped in the MR fluid.

Study on optimum arrangement of hysteretic dampers in frame structure

The earthquake mitigation effect of hysteretic dampers is not only related to the number, stiffness, strength, deformation ability of dampers but also to the strength and stiffness of the structure. This paper studied the condition that structures should be in when the hysteretic dampers mitigated seismic action most effectively and made appropriate numerical analysis to verify the effectiveness of theory derivation. The inelastic seismic responses were analyzed for the SDOF system that the shear strength ratio of the damper system was taken differently and the result showed that when the ratio was in the vicinity of the optimum strength ratio of the damper system, the displacement of the structure was minimum and the energy dissipation of dampers was maximum, which indicated that the dampers mitigated seismic action most effectively. The result also indicated that the hysteretic dampers had significant earthquake mitigation effect when the strength ratio β changed in a relatively wide range.

A linear rotary magnetorheological damper for vehicles

A new type of linear rotary magnetorheological damper (MRD) is proposed, which consists of a cylinder-type MRD and a screw mechanism to transform a linear motion into revolving motion. It is found that the structure parameters of MRD have complex relationship with the force of the damper, especially the lead angle, width and radius of the inner rotor. The analyses and simulation calculation of the static magnetic field give some usable data, and experiments of the damping component indicate that the proposed methods is feasible for developing linear rotary MRD.

Nonlinear Control Model of Synchronous Motor with Excitation and Damper Windings

In this paper, a new control method for synchronous motor with excitation and damper windings is presented. It is based on one type of nonlinear control; feedback linearization control. To make a realization in the sense of electric drive, symmetricM space vector PWM （pulse width modulation） is applied. Estimation of damper winding currents via Lyapunov function for the whole estimated system is done. The aim of control is to make tracking system for rotor speed and square of stator flux. Simulation of motor starting to predefined operating points is done, and also maintaining these points during step change of load torque is obtained. Simulations give good results.

电磁式混合动力吸振器结构设计与参数影响研究

基于最优同调和最优阻尼理论,设计了一种双环串接电磁式混合型动力吸振器;计算了动力吸振器的性能参数,包括电磁力、磁性阻尼和弹簧刚度。在此基础上,以提高动力吸振器力常数,减少漏磁通为目标,在吸振器体积和线圈腔面积不变的情况下,以永磁铁与导磁板厚度比、外永磁铁内径和内永磁铁外径、外导磁板内径和内导磁板外径为变量,对磁场结构进行仿真改进。仿真结果表明,在吸振器磁路结构体积一定时,改进后的动力吸振器的电磁力由102.3 N增加到146.6 N。

The role of magnetic damping in the r-mode evolution of accreting neutron stars

The magnetic damping rate was introduced in the evolution equations of r-modes,which shows that r-modes can generate strong toroidal magnetic fields in the core of accreting millisecond pulsars inducing by differential rotation.With consideration of the coupling evolution of r-modes,spin and thermal evolution,we investigated the influence of the magnetic damping on the differential rotation of nonlinear r-modes of accreting neutron stars.We derived the coupling evolution equations of the star involving the magnetic damping rate in the framework of second-order r-mode theory.The numerical results show that the magnetic damping suppressed the nonlinear evolution of r-modes since the saturation amplitude is reduced to a great extent.In particular,because of the presence of the generated toroidal magnetic field,the spin-down of the stars is terminated and the viscous heating effects are also weakened.Moreover,we could obtain a stronger generated toroidal magnetic field in the second-order r-mode theory.The gravitational radiation may be detected by the advanced laser interferometer detector LIGO if the amount of differential rotation is small when the r-mode instability becomes active and the accretion rate is not very high.