共查询到20条相似文献，搜索用时 31 毫秒
1.
This paper presents a bi-directional permanent-magnet linear actuator for directly driving electrohydraulic valves with low power consumption. Its static and dynamic performances were analyzed using the 2D finite element method, taking into account the nonlinear characterization and the eddy current loss of the magnetic material. The experiment and simulation results agree well and show that the prototype actuator can produce a force of±100 N with the maximum power being 7 W and has linear characteristics with a positive magnetic stiffness within a stroke of ±1 mm. Its non-linearity is less than 1.5% and the hysteresis less than 1.5%. The actuator＇s frequency response （-3 dB） of the displacement reaches about 15 Hz, and the most significant factor affecting the dynamic performance is identified as the eddy current loss of the magnetic material. 相似文献
2.
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｔｈｅｔｒａｄｉｔｉｏｎａｌｍｅｔｈｏｄｔｏｓｔｕｄｙｔｈｅｐｅｒｆｏｒｍａｎｃｅｓｏｆｉｎｄｕｃｔｉｏｎｍｏｔｏｒｓｉｓｂａｓｅｄｏｎｔｈｅｃｏｎｃｅｐｔｏｆｅｑｕｉｖａｌｅｎｔｃｉｒｃｕｉｔ.Ｔｈｅｐａｒａｍｅｔｅｒｓｉｎｔｈｅｅｑｕｉｖａｌｅｎｔｃｉｒｃｕｉｔａｒｅｕｓｕａｌｌｙｏｂｔａｉｎｅｄｂｙｍａｇｎｅｔｉｃｃｉｒｃｕｉｔｃｏｍｐｕｔａｔｉｏｎ .Ｉｎｒｅ ｃｅｎｔｙｅａｒｓｉｔｈａｓｂｅｃｏｍｅｐｒａｃｔｉｃａｌｔｏｕｓｅｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈ… 相似文献
3.
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
4.
In this paper, eddy current sensors and thermocouple sensors were employed to measure the thermal field and thermal deformation of a spindle of a telescopic CNC boring-milling machine tool, respectively. A linear regression method was proposed to establish the thermal error model. Furthermore, two compensation methods were implemented based on the SIEMENS 840D system by using the feed shaft of z direction and telescopic spindle respectively. Experimental results showed that the thermal error could be reduced by 73.79% when using the second compensation method, and the thermal error could be eliminated by using the two compensation methods effectively. 相似文献
5.
3D Magnetic Field Computation of a Permanent MagnetDisc-Type Generator Using Scalar Potential Method
The three-dimensional magnetic field of a permanent magnet (PM) disc-type generator is analyzed by the scalar potential method.
In the analysis the permanent magnets are taken as magnetic charges. Hexahedron element meshes are automatically generated
by a pre-processing program developed by the authors. The flux density is computed by a 3D scalar potential method program.
Based on the finite element analysis the induced emf, current, armature reaction effects and electromagnetic torque of the
disc machine are all calculated. 相似文献
6.
In this paper, a stabilized finite element technique, actualized by streamline upwind Petrov-Galerkin (SUPG) stabilized method
and three-step finite element method (FEM), for large eddy simulation (LES) is developed to predict the wind flow with high
Reynolds numbers. Weak form of LES motion equation is combined with the SUPG stabilized term for the spatial finite element
discretization. An explicit three-step scheme is implemented for the temporal discretization. For the numerical example of
2D wind flow over a square rib at Re=4.2×105, the Smagorinsky’s subgrid-scale (SSGS) model, the DSGS model, and the DSGS model with Cabot near-wall model are applied,
and their results are analyzed and compared with experimental results. Furthermore, numerical examples of 3D wind flow around
a surface-mounted cube with different Reynolds numbers are performed using DSGS model with Cabot near-wall model based on
the present stabilized method to study the wind field and compared with experimental and numerical results. Finally, vortex
structures for wind flow around a surface-mounted cube are studied by present numerical method. Stable and satisfactory results
are obtained, which are consistent with most of the measurements even under coarse mesh. 相似文献
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8.
基于麦克斯威尔方程,给出导电薄板的非线性磁弹性振动方程,以及磁场环境下的电动力学方程和电磁力表达式。在此基础上,应用伽辽金法导出相应的非线性振动微分方程组,研究横向恒定磁场中周期载荷作用下梁式薄板的稳定性问题。根据李雅普诺夫近似稳定性理论,对稳态解的稳定性进行分析,得到稳定性的判定条件。通过对算例特征值的求解对振动的稳定性进行分析。 相似文献
9.
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
10.
分析了磁悬浮轴承电磁力与其电流和转子位移非线性关系产生的原因,结合国内外文献资料,主要从磁轴承偏置磁场以及本质非线性两方面对磁悬浮轴承力与电流及其位移关系线性化策略进行概述。 相似文献
11.
INC Mustafa 《浙江大学学报(A卷英文版)》2005,6(10):1058-1064
INTRODUCTION The decomposition method was introduced by Adomian(1989;1994)in the1980’s for solving linear and nonlinear functional equations(algebraic,dif-ferential,partial differential equations(PDEs)and systems,integral,differential-delay,integro-differen-tial equations,etc.)(Adomian,1989;1994;Guellal and Cherruault,1995;Adomian et al.,1996;Laffez and Abbaoui,1996;Ndour et al.,1996;Guellal et al.,1997;Abbaoui and Cherruault,1999;Adjedj,1999).This method leads to computable,accurat… 相似文献
12.
利用摄动方法,研究了在外加交流电场E=E1sinωt＋E2sin3ωt＋E5sin5ωt的作用下,非线性带涂层圆柱形复合介质的电势分布,这种介质的电流密度J和电场强度E之间满足的关系为Jα=σαE＋χα｜E｜2E。 相似文献
13.
Shen Min 《上海大学学报(英文版)》1998,2(3):194-197
１ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｈｅｃａｓｅｏｆｍｅａｎｆｌｏｗａｒｏｕｎｄａ２－Ｄｏｂｓｔａｃｌｅ,ｂｒｏａｄｗａｋｅｗｉｌｏｃｃｕｒｄｕｅｔｏｔｈｅｂｏｕｎｄａｒｙｌａｙｅｒｓｅｐａｒａｔｉｏｎｗｈｅｎｔｈｅＲｅｙｎｏｌｄｓｎｕｍｂｅｒｉｓｈｉｇ... 相似文献
14.
介绍了采用FLAC30内嵌功能较强的FISH语言对初始地应力场生成方法的改进,建立了三维非线性地应力反演分析数值模型.模拟了断层及裂隙密集带,并采用此方法构造神经网络样本,采用神经网络结构分析的方式,对不同深度的侧向系数进行反演.通过正分析的计算结果与现场实测值对比,满足精度要求,表明所获得的岩体地应力场是基本合理的. 相似文献
15.
The grating eddy current displacement sensor （GECDS） for distance or position measurement used in watertight electronic calipers was described. The sensor relies on repetitive variation of inductance against displacement caused by the change of coupling areas between moving coils and static reflectors. The investigations focused on setting up and utilizing a computer model of the 3D eddy current fields and geometry to analyze causes of the production of measurement blind areas, and to investigate effects of the sensor parameters, such as axial gap between coils and reflectors, reflector length and reflector width on characteristics of the sensor. Simulation results indicated that the sensor has the smallest nonlinearity error of 0.15%, which agrees well with the experimental results. 相似文献
16.
INTRODUCTION Modelling the variation in surface-atmosphericexchange of water vapor and carbon dioxide fluxesand how they are influenced by a complex combina-tion of environment variables and plant physiology iscrucial for assessing the annual water and carbonbudget for cropland. Biophysical or process-basedmodels such as soil-vegetation-atmosphere transfer(SVAT) (Franks et al., 1997; Franks and Beven, 1999Mo and Beven, 2004), Simultaneous Heat and Water(SHAW) (Flerchinger et al., 1… 相似文献
17.
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
18.
INTRODUCTIONMostcountrieshaveimplementednewpoli ciesontheenergysavingandenvironmentpro tection.AmericanPresidentBushsigned“TheComprehensiveNationalEnergyPolicyAct”in1992statingthatnogeneral purpose ,three phaseinductionmotorswillbeallowedintoUnit edStat… 相似文献
19.
通过引入光线示波器振子系统中的非线性恢复力偶矩建立非线性振动方程,分析可以诱发振子系统主共振的条件。应用多尺度法得到振子系统满足主共振情况下的近似解,并进行数值计算。讨论磁感应强度、电流信号强度、阻尼对振子系统的影响,表明增大振子系统的磁感应强度或电流信号的强度可以增大系统主共振的振幅和共振区,增大振子系统阻尼可以减小系统主共振的振幅和共振区,反之亦然。 相似文献
20.
概述了二滩水电站地下厂房洞室群的超大规模的、模拟开挖过程的三维非线性有限元分析，以及分析中的一些全新的处理方法．据此，对地下洞室群三维非线性FEM分析中若干具有共性的问题提出了看法、讨论与建议，包括：在地应力丰方向与洞室轴线不平行时，地下洞室群进行三维非线性分析不可替代性；地应力场的获得与校核对得出合理计算结果的重要意义：有限元建模中数值误差与理论简化相适应，以保证计算的合理性与可行性；开挖步骤的模拟对非线性分析中发现破坏位置和破坏时间必要性等．此外，对部分计算结果进行简要的分析． 相似文献