基于ANSYS的大型电机定子铁心振动特性分析

为了降低大型电机的电磁噪声,有必要分析定子铁心的振动特性。文中采用ANSYS软件对定子铁心进行模态分析,得出其振动固有频率和振型,此外,还重点探讨了弧形板、压圈、绕组、通风槽和肋等构件对定子铁心振动特性的影响。研究表明,弧形板对定子铁心振动特性无影响;压圈、通风槽和肋对定子铁心的低阶固有频率无影响,但对高阶固有频率影响较大;绕组对定子铁心的振动特性影响很大。     

大型异步电机结构振动特性的研究

精确计算电机的固有频率和响应,对于预测电机的振动和噪声是至关重要的.文中利用三维有限元分析研究大型感应电机定子的振动模态和固有频率,并分析绕组、端盖、连接筋及安装方式对电机定子固有频率和振动模态的影响;研究表明,对于大型异步电机,定子绕组对固有频率和振动模态有显著的影响,安装端盖和机座固定使定子固有频率上升,通过改变机座及端盖结构可改变定子固有频率,避免发生共振,采用弹性连接筋,可有效减小定子振动的传播.实验验证部分计算结果.     

UMT60行波型超声电机定子模态分析

超声电机定子结构的振动特性决定了该结构对各种动力荷载的响应情况,对UMT60行波型超声电机定子进行模态分析,得到定子的振动特性,即固有频率和振型,为超声电机的各种动力分析提供依据.     

机座影响下的电机定子固有频率计算

电机的振动噪声和电机结构参数密切相关,为避免电机定子的共振,在设计阶段对电机定子进行模态分析具有重要意义。论文考虑了机座对电机定子振动固有频率的影响,给出了计算定子与机座耦合系统的固有频率的解析计算法,并通过ANSYS有限元方法进行了验证,结果证实两者能够很好的吻合。     

异步电机定子模态分析

定子模态分析是异步电机设计的重要步骤。本文利用有限元法建立了型号为YXKK710-6TH电机定子的有限元模型,并对此电机定子进行模态分析,得出了定子的理论固有频率,同时对该型号的电机定子进行了定子模态测试,结果表明:分析结果与实测结果基本接近。相关研究结论为电机的整体结构设计及振动特性分析提供了有益的参考。     

电气设备的诊断技术（5）

(2)电机机械系统的振动特性 前面已阐明电磁激振力的大小与频率及模态形状。它们是由于电磁力的作用,使电机的定子铁芯振动并进一步将这一振动传递到框架而发生的振动。由于定子铁芯较厚,刚性也高,所以铁芯框架组成的机械系统的动刚度基本上由铁芯所决定。 为避免出现振动和噪声问题,应使机械系统的固有频率远离电磁激振力的频率。因此必须了解有关电机定子铁芯固有频率的知识。 ①定于铁芯的固有频率及振动模态。感应电机由于前述的电磁力的作用,铁芯一框架机械系统以固有模态形式及固有频率振动。感应电机根据其结构,二极电机m=2(椭圆模态),四极电机m=4(4角形模态),以相应的形式振动,并放射出声音(图7)。     

立式电机定子模态有限元仿真及试验研究

以某立式电机为原型,建立了电机定子的真实三维实体模型,用有限元方法建立了动力学分析模型.在MSC.Nastran环境下,进行了定子的模态仿真分析,研究了其固有振动特性,得到了定子前6阶固有频率和振型.进行了定子的模态试验,试验数据与仿真分析结果对比表明,两种方法结果接近.研究成果既反映了电机的动力学性能,又为电机的动态特性分析奠定了基础.     

兆瓦级双定子直驱风力发电机定子振动研究

精确计算发电机的固有频率,对于预测发电机的振动和噪声至关重要。利用三维有限元分析研究兆瓦级双定子风力发电机三种定子结构的振动模态和固有频率,并分析了其振动特点。分析结果表明,外定子、内定子和双定子结构的固有频率均有效避开了发电机系统不平衡激振频率和所发出的交流电频率。本文的方法可用在发电机设计阶段对定子固有频率进行预测。     

环形超声电机定子的振动模态与谐响应分析

振动模态分析和谐响应分析是超声电机优化设计的重要步骤。基于本实验室提出的压电定子和压电转子振型嵌合式环形超声电机,利用有限元软件Ansys10.0建立了直径为60 mm的环形超声定子的模型,并对此电机定子进行模态分析以及谐响应分析,得出了定子的固有频率和振型以及理论振幅值,特别阐述了此电机定子最优振动模态的选择。同时利用Agilent 35670A对制作的电机定子进行扫频测试,结果表明:分析结果与实测结果基本接近。研究结论为超声电机的优化设计提供了理论依据。     

行波超声电机的运转特性及其电学建模研究

首先建立了压电层合梁的压电振动方程,并引入六端等效电路对振动进行描述。再根据电机定子与压电梁的结构对应关系,推导出定子的导纳频响方程,并给出理想定子的等效电路;针对定子在其工作频区的导纳特性,构建出定子的二端等效电路;在对耗损、预压力、负载、温度等因素建模基础上,构建出电机完整的等效电学模型。最后,通过电机扫频试验验证了所建立模型的有效性。     

Theoretical and experimental study of vibrational behaviour of laminated stators of electrical machines

An accurate determination of the resonant frequencies and vibrational characteristics of a stator is essential in the design of quiet electrical machines. This paper presents both a fundamental theoretical and an experimental study of the vibrational behaviour of long and short laminated stators of electrical machines. The paper describes briefly the method of analysis, based on the three-dimensional theory of elasticity, for free vibrations of stators with encased construction. To prove the general validity of the analysis and to study the effect of windings, frame, and impregnation upon the resonant frequencies and vibrational behaviour of the stators of electrical machines, extensive experimental investigations were conducted on a number of stator models which include a solid model, long laminated, and short laminated models with and without windings, frame and impregnation. The paper compares the experimental and analytical results for some of these models which prove the general validity of the analysis. Finally, the paper also includes the important findings of these extensive investigations.     

Electrothermal effects of advanced electromagnetic materials on electrical loss and thermal characteristics of synchronous rotational machines

Electrothermal characteristics of high speed synchronous rotational machine were studied experimentally and theoretically. Electrical rotating machines with three types of electromagnetic materials were fabricated to identify core losses in the iron cores of high speed synchronous machine. Dummy and isolated rotational machines were devised to measure pure mechanical losses and to examine conductive thermal resistances in stators. Results showed that mechanical losses are linearly proportional to driving speeds of electrical rotating machines, and that viscosity-induced mechanical losses in air are relatively negligible in comparison with friction-induced mechanical losses. It was found that an electrical rotating machine with 15HTH1000 electromagnetic material has relatively lower core and coil losses than the machines with 35PN440, 35PN250, thereby making it applicable for advanced high speed electric vehicular applications. In addition, core materials had a negligible effect on torque constants of the electrical rotating machines at a lower non-dimensional rotational speed of 0.2. However, the rotating machine with 15HTH1000 showed an 8.0% higher input current than did that with 35PN440 at a higher rotational speed of 0.9. Finally, thermal resistances in between iron cores and stators could be accurately characterized by a nonlinear empirical formula with the minimum R² value of curve fittings equal to 0.997 which reflects the convection effects on heat transfer enhancement.     

A homotopy perturbation analysis of nonlinear free vibration of Timoshenko microbeams

This paper uses He’s Homotopy Perturbation Method (HPM) to analyze the nonlinear free vibrational behavior of clamped-clamped and clamped-free microbeams considering the effects of rotary inertia and shear deformation. Galerkin’s projection method is used to reduce the governing nonlinear partial differential equation. to a nonlinear ordinary differential equation. HPM is used to find analytic expressions for nonlinear natural frequencies of the pre-stretched microbeam. A parametric study investigated the effects of design parameters such as applied axial loads and slenderness ratio. The effect of rotary inertia and shear deformation on the nonlinear natural frequency was investigated. For verification, a numerical approach was implemented to solve the nonlinear equation. of vibration. A comparison between analytical and numerical results shows that HPM can predict system nonlinear vibrational behavior significantly more accurately than previously used methods in the literature.     

Models of vibrational transfer and filtration of vibroimpact processes

Examples of the appearance of vibrational motion modes, which lead to excess noise and premature wear of machine parts and mechanisms are presented. Models of mechanical filters of various types are considered, and the problems of the nonlinear and linear filtration of wave-vibrational processes are discussed. The models of the vibration-conducting media, involving the nonlinear vibrational guides of a complex structure, are presented. The analytical studies of the problems associated with the passage of periodically strongly nonlinear (vibroimpact) processes through the multidimensional machine designs, which are modeled by means of discrete 2D mechanical systems with regular structures, or multidimensional mechanical filters for low frequencies, are performed. The physical sense of the derived solutions is obtained, the computational formulas are derived, and the main dynamic effects are discussed. The notion of filter metrics is introduced.     

大型分体式磁轴承电动机系统定子模态分析

准确分析定子固有模态对低振动噪声电机系统优化设计和控制有十分重要的意义。针对大型分体式磁轴承电动机系统,采用有限元仿真方法分析轴向磁轴承定子绕组、径向磁轴承定子叠片结构、机座螺栓连接以及底座附加质量对大型分体式磁轴承电动机系统定子模态的影响。结果表明:轴向轴承定子绕组对定子固有频率影响较大,宜采用质量计入铁心的方式处理;径向轴承定子叠片结构对定子固有频率的影响较小,可按各向同性处理;机座螺栓连接刚度对机座固有频率有一定影响,但当连接刚度远大于机座刚度时,影响较小;底座附加质量对整机模态频率有一定的影响,但对不同振型的固有频率的影响效果相差较大。计算了整机的模态频率,并与振动试验结果进行了对比验证。     

基于边界元法的混联数控机床整机结构动态特性解析

基于边界元法研究混联数控机床整机结构动态特性的解析和建模方法。首先采用粱单元、集中质量单元、弹簧单元及结合部单元建立混联机床整机结构动力学模型，基于边界元方法建立各单元的动力学方程式，通过单元合成方法推导出混联数控机床整机结构动力学方程，用频率扫描法得到整机结构的固有频率。基于所建立混联机床结构动态特性解析方法，开发相应的整机动态特性解析软件，实验证明，所建立混联机床整机动态特性解析方法及开发的软件是可靠的，不仅可以为混联数控机床加工过程中回避薄弱位姿状态提供依据，而且可以为混联数控机床的结构设计提供理论依据，对提高混联数控机床的设计水平具有重要意义。     

Vibration of nonuniform carbon nanotube with attached mass via nonlocal Timoshenko beam theory

This paper studies the vibrational behavior of nonuniform single-walled carbon nanotube (SWCNT) carrying a nanoparticle. A nonuniform cantilever beam with a concentrated mass at the free end is analyzed according to the nonlocal Timoshenko beam theory. A governing equation of a nonuniform SWCNT with attached mass is established. The transfer function method incorporating with the perturbation method is utilized to obtain the resonant frequencies of a vibrating nonlocal cantilever-mass system. The effects of the nonlocal parameter, taper ratio and attached mass on the natural frequencies and frequency shifts are discussed. Obtained results indicate that the sensitivity of the frequency shifts on the attached mass increases when the length-to-diameter ratio decreases. Tapered SWCNT possesses higher fundamental frequencies if the taper ratio becomes larger.     

面向寿命终结阶段的机械产品设计绿色多准则优化

针对机械产品设计过程中通常考虑产品寿命终结阶段(End-of-life,EOL)报废处理过程的可拆卸性、再制造性、环保性等单个绿色质量因素影响,导致机械产品的回收拆解中可重用、回收零部件由于拆解过程费事、费力、经济性差无法回收重用或因回收重用价值不大导致零部件被直接废弃,造成严重的环境污染.从回收拆解作业效率、回收拆解...     

Dynamic characterization of machining systems

In the working space model of machining, an experimental procedure is implemented to determine the elastic behaviour of the machining system. In this paper, a dynamic characterization and vibration analysis has long been used for the detection and identification of the machine tool condition. The natural frequencies of the lathe machining system are required (Ernault HN400??France) according to three different situations with no cutting process are acquired. The system modal analysis is used to identify the natural frequencies. These frequencies are then compared to the ones obtained on the spindle numerical model by finite element method. This work is validated by experimental tests based on measures of the lathe machine tool frequencies domain. The main objective is to identify a procedure giving the natural frequency values for the machine tool components, in order to establish a better condition in the cutting process of the machine tool.