共查询到20条相似文献，搜索用时 499 毫秒
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lintroductionInrecent20years,owingtotilerapiddevelopnlentofco.nputertechnology,tiletiniteelenlent1netnodforstndyingelectronlagneticfieldwasdevelopedti.onltheoreticalconlputationtoconnnercialsoftwarepackageinvestigation,towardstiledirectionofCAD,andgradnan… 相似文献
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由于磁通量的变化,交变磁场中的导体中会感生涡流,产生涡流反过来会产生磁场,与交变磁场形成斥力作用,利用此斥力作用可以实现导体的悬浮。利用此原理制作了磁悬浮实验,涡流的存在得到了验证。结果表明,交变磁场变化越大,悬浮对象材质越轻,截面积越大,悬浮效：果越好。此外,利用涡流的不均匀分布制作了驱动装置。 相似文献
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A novel ε-type solenoid actuator is proposed to improve the dynamic response of electro-pneumatic ejector valves by reducing moving mass weight. A finite element analysis （FEA） model has been developed to describe the static and dynamic operations of the valves. Compared with a conventional E-type actuator, the proposed ε-type actuator reduced the moving mass weight by almost 65% without significant loss of solenoid force, and reduced the response time （RT） typically by 20%. Prototype valves were designed and fabricated based on the proposed ε-type actuator model. An experimental setup was also established to investigate the dynamic characteristics of valves. The experimental results of the dynamics of valves agreed well with simulations, indicating the validity of the FEA model. 相似文献
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Compared to the current eddy braking patterns using a single magnetic source, hybrid excitation rail eddy brakes have many
advantages, such as controllability, energy saving, and various operating models. Considering the large braking power consumption
of the high-speed train, a hybrid excitation rail eddy brake system, which is based on the principle of electromagnetic field,
is proposed to fulfill the needs of safety and reliability. Then the working processes of the mechanical lifting system and
electromagnetic system are demonstrated. With the electromagnetic system analyzed using the finite element method, the factors
such as speed, air gap, and exciting current have influences on the braking force and attractive force. At last, the structure
optimization of the brake system is discussed. 相似文献
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Experimental Study on Magnetorheological Damper for Semi-Active Vibration Control of Civil Infrastructures 总被引：3，自引：0，他引：3
Magnetorheological (MR) fluid is a kind of smart material whose rheological properties can be rapidly varied in magnetic field. To make full use of the advantages of MR fluid to devices, a model of double-ended,shear-combined and valve-typed MR damper is designed and manufactured, and the dynamic properties under sinusoidal excitations are experimentally studied. The experiment results show that the maximum damping force of the MR damper at the full magnetic intensity reaches about 20 k while the maximum power required is less than 50W, which predicts that the MR damper will be a powerful measurement for semi-active vibration control of civil infrastructures. 相似文献
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祝长生 《浙江大学学报(A卷英文版)》2003,4(5)
A disc-type magneto-rheological fluid damper operating in shear mode is proposed in this paper, which is based on the special characteristics of the magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its rheological properties by the application of an external magnetic field. The magnetic field of the disc-type MR fluid damper is analysed by the finite element method; the controllability of the disc-type MR fluid damper on the dynamic behaviour of a rotor system; and the effectiveness of the disc-type MR fluid damper in controlling the vibration of a rotor system, are studied in a flexible rotor system with an over-hung disc. It is shown that the magnetic flux density of the disc-type MR fluid damper in the working areas can significantly change with the applied current in the coil; and that the dynamic behavior of the disc-type MR fluid damper can be varied by the application of an external magnetic field produced by a low voltage electromagnetic coil. The disc-type MR fluid damper can significantly change the dynamic characteristics of a rotor system, provided that the location of the disk-type MR fluid damper is carefully chosen. The disc-type MR fluid damper is a new actuator with good dynamic characteristics for rotating machinery. 相似文献
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林抒毅田源黄晓生孔毅鹏俞智坤 《福建工程学院学报》2020,(3):260-266
针对四线圈非理想耦合对系统输出电流特性的影响,采用等效容性耦合的方法来实现理想的四线圈系统电流输出特性。 首先结合补偿电感的磁集成,减少了无线电能传输系统磁元件数量并缩小其体积,再对等效电路参数的设计进行分析并设计了实验样机。 实验结果验证了容性耦合等效方法的准确性与有效性。 在负载范围内,样机接收端直流输出电流的波动小于8%,传输距离为75 mm时整机输出功率为300 W,效率峰值达到了81.49%。 相似文献
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１ＩｎｄｕｃｔｉｏｎＬａｄｌｅＦｕｒｎａｃｅａｎｄＩｔｓＴｅｃｈｎｉｃａｌＰｒｏｐｅｒｔｉｅｓＩｎｄｕｃｔｉｏｎｌａｄｌｅｆｕｒｎａｃｅ（ＩＬＦ）ｉｓａｒｅｃｅｎｔｌｙｄｅｖｅｌｏｐｅｄｅｑｕｉｐｍｅｎｔｆｏｒｓｅｃｏｎｄａｒｙｒｅｆｉｎｉｎｇａｎｄ... 相似文献
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基于适当的假设和近似, 通过分析电涡流的分布、洛伦兹力、磁致伸缩力和磁化力, 研究了在铁磁材料中用电磁声换能器(EMAT)的方法产生超声的耦合机理, 并针对有实用意义的结构参数进行了数值计算以解释换能器的性能. 结果表明: 对于铁磁性材料, 在磁场强度较低、材料磁化未达到饱和时, 磁致伸缩效应在EMAT超声波的产生中起主导作用; 但是, 随着偏置磁场的逐渐增强而使材料达到磁化饱和时, 磁致伸缩逐渐消失, 对产生超声不再有贡献作用, 洛伦兹力变成是激发超声的惟一原因. 因此, 为获得优化的设计, 计算洛伦兹力和磁致伸缩力以及选择合适的工作方式变得尤为重要. 相似文献
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INTRODUCTIONElectro rheological (ER ) Magneto rheologi cal(MR)fluidisakindofcontrollablefluidwhoserheologicalproperties,especiallyapparentviscosity,canbedramaticallyandreversiblyvariedinafewmillisecondsbytheapplicationofanexternalelectrical magneticfield… 相似文献
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Zhu Chang-sheng 《浙江大学学报(A卷英文版)》2003,4(5):514-519
A disc-type magneto-rheological fluid damper operating in shear mode is proposed in this paper, which is based on the special
characteristics of the magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its rheological properties
by the application of an external magnetic field. The magnetic field of the disc-type MR fluid damper is analysed by the finite
element method; the controllability of the disc-type MR fluid damper on the dynamic behaviour of a rotor system; and the effectiveness
of the disc-type MR fluid damper in controlling the vibration of a rotor system, are studied in a flexible rotor system with
an overhung disc. it is shown that the magnetic flux density of the disc-type MR fluid damper in the working areas can significantly
change with the applied current in the coil; and that the dynamic behavior of the disc-type MR fluid damper can be varied
by the application of an external magnetic field produced by a low voltage electromagnetic coil. The disc-type MR fluid damper
can significantly change the dynamic characteristics of a rotor system, provided that the location of the disk-type MR fluid
damper is carefully chosen. The disc-type MR fluid damper is a new actuator with good dynamic characteristics for rotating
machinery.
Project supported partially by the EC BRITE/EURAM program under BRPR-CT97-0544 IMPACT project and State Key Laboratory of
Vibration, Shock and Noise, Shanghai Jiatong University 相似文献
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Yun-guang Luan Hua-ming Wang Dong-biao Zhao Yang Wang Feng-hong Chen 《浙江大学学报(A卷英文版)》2017,18(10):831-840
A combustion-powered actuator has been proposed in our previous work (Wang et al., 2015), and it has shown great power hopping ability. To explore the hopping process and output performance of the actuator, the model of an actuator driving the hopping process is investigated through theoretical analysis and experimental validation. Firstly, the structure of the actuator and hopping process are described briefly, and the dynamic models of the process are constructed. Secondly, the thermodynamic model of the actuator is established by the Wiebe heat release function and the input energy density is computed by Chemkin for when propane and nitrous oxide with different equivalence ratios are injected into the chamber. Thus, the thermodynamic model is obtained by integrating dynamic and thermodynamic equations. After that, a few output performance parameters are identified to assess system performance. Lastly, the experimental rig of the combustion actuator is set up to test the displacement and pressure of the actuator driven hopping process. By solving the thermodynamic equations, the post-combustion pressure, the displacement and the velocity varying with time are computed, and are compared with the test results, indicating that the computational results match the experimental test well. At the end of the stroke, the velocities of the experiment and simulation are 6.5 m/s and 6.99 m/s, respectively. The hopping results are compared with the simulation when different pressures under equivalence ratio of 1 are injected, and the maximum and minimum deviations are 14.45% and 1.83%, respectively. 相似文献
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Ion-exchange polymer-metal composite （IPMC） is a new electroactive material. It has large deformation and high force weight ratio in the presence of low voltage （〈1.5 V）. In this study a soft actuator known as artificial muscle based on IPMC was prepared. The IPMC actuator is composed of a perfluorinated ion-exchange membrane and platinum plated on both sides of the membrane by chemical means. Experiences and some key points are introduced in preparation of the IPMC. Electromechanical behaviors of the actuator are investigated, Factors related to the actuator performance are discussed. 相似文献
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李俊华 《常熟理工学院学报》2009,23(8):83-85
在单自由度磁悬浮系统中,为了得到转子的稳定悬浮,必须由系统中的位移传感器提供转子的准确位置信息．这就要求对传感器测得的电压信号进行处理,这些信号在很大范围内是非线性的,从而限制了其测量范围．为了使转子在大范围内稳定悬浮,需要对传感器的信号作线性处理．本文根据所测得的电涡流位移传感器的特性曲线,用软件补偿的方法对此传感器进行了线性补偿,从而扩大了传感器的线性范围．实践表明,用此方法对传感器线性补偿后,转子的稳定悬浮范围扩大很多． 相似文献
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为测量单托辊传送带在传输状态下固体散料的动态重量,采用称重传感器连续采样计量区段传输带托辊所受到的压力,用电涡流传感器测量放大后的辊轴瞬时速度,将采集的两路电压信号调理后,用测速法计算物料的瞬时重量和累积重量。动态称重系统采用虚拟仪器技术完成信号的采集和调理,上位机采用LabVIEW软件实现计算和显示,原理简单,精度高,易实现,具有较高的实用性。 相似文献
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发散波作用下粒子速度的二维电磁测试关键技术包括恒定强磁场、动态载荷与磁场同步、交叉干扰项信号消除等.研究并设计了米级尺度的Helmholtz线圈,对Helmholtz线圈施加脉冲电流,获得了持续时间8.26～30.62 ms的恒定磁场平台,峰值波动误差为0.1％～1.0％.设计了新型二维发散波电磁粒子速度计,采用“对称双S型”布局感应线圈,消除干扰项,获取有效的微弱信号.有机玻璃样品中粒子速度的一维和二维电磁测试对比实验结果表明:粒子速度首峰值随爆心距的变化关系、信号时间特性符合物理规律.为有分界面、沟槽或节理的非均匀分层介质中发散波传播规律研究提供了有效的测试手段. 相似文献
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The passive electromagnetic damper has the same configuration as that of the electromagnetic bearing, but no sensors and no closed loop control are needed. Its robustness and no-contact structure are its great advantages. When the rotor vibrates, the electromagnetic field intensity in the air gap is altered, then fluctuating currents in the damper coils and eddy currents inside the surface layer of rotor are created. Damping force is caused by the fluctuating currents, while retardation torque is generated by eddy currents. The characteristics of a damper may be improved by adding an additional electrical circuit. Numerical studies showed that damping coefficient increases with increasing static current, but decreases with increasing frequency. And the damping coefficient of the improved damper at higher frequency is more evident than that of the original damper. Experimental results showed that the resonant vibration around the first critical speed was obviously suppressed by both types of passive electromagnetic damper. 相似文献