ANSYS在永磁电机转子强度接触有限元分析中的应用

扼要地介绍了ANSYS有限元软件求解接触问题时涉及到的基本概念和原理,介绍了接触有限元分析的具体步骤.应用大型有限元分析软件ANSYS,考虑永磁电机转子中永磁体和转子铁心的接触非线性状态,对永磁电机转子进行了三维有限元分析,得出了永磁电机转子的应力分布情况.整个分析求解过程也为类似的接触有限元分析提供了参考.     

转子静偏心状态下机床电主轴电磁力有限元分析

电磁振动是电磁直驱型机床电主轴不可回避的振动来源,为了抑制电磁振动需要探讨其电磁力的频谱特征。推导了三相异步电主轴的电磁力波计算公式,重点分析了转子偏心状态下的电磁力波特点。基于Ansoft电磁场计算软件,建立了某国产电主轴的电磁场有限元分析模型,获得了电主轴的运行特性曲线。研究了转子在不偏心和偏心状态下的电磁力频谱变化规律,结果表明,静偏心会使电磁力力波成分更为丰富; 偏心的增加不会影响电磁力的阶次和频率分布,但与不平衡磁拉力的幅值和低阶力波幅值成正相关关系,将加剧电主轴的振动。     

浅析感应电机转子偏心问题解决办法

本文主要是研究感应电机转子偏心问题的解决方案,在基础的电流频法中指出常规的FFT的不足还有它的优势,随着工业的迅速发展,感应电机以其结构简单、价格低廉、可靠性高、方便简单被广为认知和使用。感应电机转子问题已经成了热门的课题之一,其中偏心问题是较为复杂的。以感应电动机为例在ANSYS中仿真分析感应电机的正常、动偏心、静偏心三种状态下的径向电磁力,来获得它们的状况和特性,电机的径向电磁力波影响着感应电机偏心的故障问题。     

制冷压缩机电机转子不平衡电磁力计算与改善

在旋转式压缩机的装配过程中,电机一般采用悬臂梁式安装方式,会造成转子偏心,电机磁路不对称,产生不平衡磁拉力,进而导致电机转子与定子相互碰撞。以某型号压缩机为例,根据麦克斯韦应力张量法与交流电磁铁理论,建立了电机径向不平衡电磁力计算模型,采用有限元Ansoft Maxwell软件进行仿真。并将径向不平衡电磁力的计算结果输入到有限元软件,根据模拟结果,提出将定子向下移动5 mm的改善方案。经过后期试验验证,改善后的电机不仅不平衡磁拉力有所减小,而且压缩机主要工作性能不会降低。     

转子三维偏心下气体箔片轴承的静、动态承载特性分析

为分析转子三维偏心下气体箔片轴承的静、动态承载特性,通过引入2个偏心角来描述转子三维偏心状态,并建立了三维偏心下气体箔片轴承的静、动态承载特性及轴承-转子系统动力学计算模型。以某气体箔片轴承为例,分析了其静、动态承载特性及转子动力学特性,结果表明：转子的三维偏心会导致气膜力分布在轴向上偏移;随转速增大,气膜的各向等效刚度、等效阻尼均不接近于0;随偏心角增大,气膜的各向等效刚度、等效阻尼近似呈指数增大;转子的运转从初始的三维偏心过渡至稳定时的二维偏心,最终在平衡位置处以低频、小振幅的振动形式稳定运转。     

无轴承永磁同步电动机径向力模型

将麦克斯韦张量法和磁路分析法相结合,提出了一种计算无轴承永磁同步电动机径向力的方法,建立了考虑转子偏心位移的径向力模型,利用有限元分析方法对表面贴装式无轴承永磁同步电动机进行仿真研究,结果表明,利用该模型能够获得较好的建模精度,验证了麦克斯韦张量法建模的正确性和可行性。     

偏心效应下大范围转动弹性梁振动特性分析

计及转子偏心效应,借助转子动力学理论,应用Galerkin法和Hamilton原理建立电机-弹性梁系统动力学模型;采用Runge-Kutta法实现动力学解耦,解析不同速度下大范围转动弹性梁的动力学特性,对比分析电机转子动偏心、静偏心与转动梁振动特性的耦合关系。研究结果表明：转子动偏心与系统动力学响应呈现强耦合,动偏心距达到0.5 mm时,转动梁振幅高达2 mm;而静偏心距由0 mm增至0.5 mm时,其振幅均为0.178 mm,后续研究可忽略静偏心因素;随着角速度提高至150 rad/s时,在转子动偏心的作用下,弹性梁振动由周期振动变为非周期振动,也是该类机构高速下呈现不同程度的突发性或间歇性振动的主要原因之一。     

电动机轴承转子多频激励系统主共振分析

以三相异步电机轴承转子系统为研究对象,考虑转子在偏心力、轴承反力和不平衡电磁力影响。应用牛顿定律建立了电机轴承转子系统非线性振动方程。应用平均法,解析系统主共振的一次近似解和对应的定常解,并进行数值计算。分析转子偏心距、转子刚度和电磁参数等对主共振幅频响应曲线的影响。     

双转子异步电动机电磁场的有限元分析

本文主要讨论了双转子异步电动机设计中电磁场的分析问题,对电机进行了有限元分析,并采用ANSYS软件建立其二维有限元模型,通过仿真得到电磁场的分布.与普通异步电动机相比,双转子异步电机的磁场耦合度和磁感应强度都有明显的提高.最后通过对样机的测试,很好的验证了仿真结果,证明了双转子异步电动机能提高功率因数和效率,是一款理想的高效节能电机.     

径向磁力轴承多因素耦合研究

采用理论计算与数值模拟相结合的方法,研究纯电磁磁力轴承的耦合问题,讨论转子存在偏心下的径向磁力轴承耦合情况。结果表明:耦合力的理论值较仿真值的相对误差随转子偏心距和工作电流的增大而增大,当偏心距为±0. 3 mm时,相对误差达到25%,理论计算公式不再适用;当偏心距为±0. 2 mm时,理论值和仿真值吻合较好。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.