永磁齿轮的理论研究和有限元分析

在现代化生产中,永磁齿轮传动是一种新型传动方式.通过将永磁齿轮和传统齿轮的对比,得到了永磁齿轮传动的优点,并总结说明了永磁齿轮与传统齿轮的差别.通过对永磁齿轮传动原理的研究,分析了传动性能的影响因素.建立了永磁齿轮的物理模型和数学模型,引入了永磁齿轮传动的数值计算方法.最后采用有限元分析对永磁齿轮传动进行了模拟和计算,...     

仿生球形凹坑表面形态对旱地洋葱插秧机高速齿轮动力学特性的影响分析

分插机构中高速齿轮的传动性能直接影响着旱地洋葱插秧机的插秧精度与使用寿命。以工程仿生学和有限元理论为基础,为实现齿轮的参数化建模,在SolidWorks软件中建立了高精度齿轮模型,运用ANSYS Workbench软件分析了仿生球形凹坑表面形态齿轮的动力学性能。通过对普通齿轮和仿生球形凹坑表面形态齿轮(仿生齿轮)进行模态分析及静力学分析,分别计算出前10阶固有频率及振型,同时分析了其接触应力与应变状态,并用nCode软件对仿生齿轮和普通齿轮进行了疲劳寿命分析。结果表明,相对于普通齿轮,仿生齿轮的各阶最大振幅更小,其固有频率数值和范围明显减小,整体趋势更加平稳。仿生齿轮可改善接触应力分布状态,减小接触应力,还能存储磨屑并形成局部油池,从而降低齿轮的磨损程度。仿生齿轮的最大疲劳损伤和最小疲劳寿命相对于普通齿轮分别减小了27.64%和增大了38.16%,有效改善了齿轮的力学性能,提高了齿轮传动的可靠性和使用寿命。     

基于UG的椭圆锥齿轮的仿真加工

椭圆锥齿轮是球面大端节曲线为椭圆的非圆锥齿轮。根据齿轮空间啮合原理和渐开线齿轮齿廓成型原理,提出了一种利用UG仿真加工获得椭圆锥齿轮齿形的方法;当圆锥齿轮的节圆在非圆锥齿轮节曲线上作纯滚动时,圆锥齿轮的齿廓便在非圆锥齿轮上包络出齿轮的齿廓。因此,首先建立了圆锥齿轮和椭圆齿轮的数学模型和几何模型,其次推导出了模拟纯滚动的数学方法,最后利用UG的二次开发功能仿真加工得到带有渐开线齿廓的椭圆锥齿轮模型。     

基于粉末冶金的少齿数齿轮传动研究

简述了少齿数齿轮传动及粉末冶金齿轮的特点,综合少齿数齿轮齿轮传动及粉末冶金的优点,提出了基于粉末冶金法设计制造少齿数齿轮的方法,对基于粉末冶金的少齿数齿轮传动的设计进行了讨论,为少齿数齿轮传动的研究及应用提供了新的思路。     

齿轮疲劳裂纹萌生与扩展行为研究现状

齿轮传动的综合效率直接制约着交通、建筑、风电等领域的发展质量,因此,对齿轮传动功率、负载能力以及预期寿命等的要求在逐步提高;然而,齿轮疲劳失效极大地限制了现代齿轮设备的性能与可靠性。综合论述了齿轮疲劳裂纹萌生与扩展行为现状,对齿轮失效的主要形式和原因进行介绍;归纳了影响齿轮疲劳强度的因素,总结了齿轮裂纹3种类型以及裂纹萌生与扩展的原因和方法;归纳了现有的齿轮疲劳裂纹模拟方法,描述了齿轮疲劳中的微结构力学行为,以提高对齿轮疲劳的特征和机制的理解;分析了在齿轮疲劳试验下的剩余使用寿命,并对如何避免齿轮裂纹产生提出了一些建议。     

齿轮传动系统的动力学与模态分析

为了提高齿轮设计的准确性,结合UG软件参数化建模功能,建立齿轮传动三维实体模型。利用ADAMS软件对齿轮传动系统进行了动力学分析,在高速传动中施加实际传动载荷,得到了齿轮传动系统的振动频率范围和高频率点。通过ANSYS Workbench软件对齿轮传动系统和单一齿轮模型进行模态分析,得到齿轮传动系统和齿轮模型的固有频率和振型,通过与动力学分析得到的频率进行对比,验证了齿轮传动系统的设计准确性,从而为今后齿轮的传动分析提供了数据支持,并为传动过程中的故障分析提供了参考。     

基于OpenGL的齿轮传动数字化设计与仿真

对渐开线标准齿轮的齿廓曲线和齿轮传动建立了精确的数学模型.在Visual C++平台上,结合OpenGL实现了直齿轮和斜齿轮的三维精确造型,基于OpenGL双缓存技术,实现了齿轮传动的运动仿真.齿廓曲线数据可以进一步应用于齿轮的数控加工,齿轮传动仿真的实现,验证了齿轮数学模型的正确性,也可应用于虚拟样机建模.     

内外啮合齿轮马达的转矩脉动分析

提出了一种新型的内外啮合齿轮马达。该齿轮马达的小齿轮与共齿轮形成内啮合齿轮马达,大齿轮与共齿轮形成外啮合齿轮马达,比传统齿轮马达在一个壳体中多了一个齿轮马达,实现了液压系统的节能与简化。在对该新型内外啮合齿轮马达理论排量和转矩进行了分析后,得出其在不同工作方式下排量与转矩的公式以及齿数对转矩脉动性的影响,即齿数越多该马达的转矩脉动性越小,为以后更好的设计出性能完善的内外啮合齿轮马达奠定了基础。     

基于齿轮传动影响因素的优化设计

从影响齿轮传动的若干因素着手,分析了齿轮传动失效原因和齿轮优化设计方法,阐述了齿廓曲线、齿轮材料对齿轮的影响及应用特点.提醒设计人员齿轮设计应按优化方式进行.     

范成法加工内平动全摆线齿轮分析

内平动全摆线齿轮的齿廓完全由内外摆线构成,根据齿轮啮合原理及摆线的基本性质,由全摆线齿轮的齿廓方程推导出了全摆线齿轮加工刀具的理论齿廓方程,并探讨了内平动全摆线齿轮的加工方法,证明了全摆线齿轮应用在内平动齿轮机构的可能性,为正确设计内平动全摆线齿轮提供了理论依据。     

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.