基于Pro/E的少齿数齿轮轴参数化设计问题研究

基于三维CAD技术,提出了一种少齿数齿轮轴参数化建模方法。针对少齿数齿轮的斜齿及变位特点,对普通圆柱斜齿轮常用的建模方法中存在问题进行了分析研究,给出了少齿数齿轮轴的精确建模设计方法,从而减少了后续的设计误差与有限元分析误差。     

少齿数齿轮传动系统动态特性分析

针对少齿数齿轮在啮合过程中发生受迫振动问题,采用基于模态叠加法的谐响应分析技术,采用Pro/E软件对少齿数齿轮传动系统进行三维建模,利用有限元分析技术对少齿数齿轮传动系统的动态特性进行了研究。基于模态分析理论,求解得到少齿数齿轮传动系统的固有频率和振型,结果表明,第2阶和第4阶模态振动对轴承安装部位影响最大。     

基于ANSYS的少齿数齿轮模态分析与研究

考虑到少齿数齿轮传动在实践中的诸多优点以及大变位和"削顶"的特点,通过Pro/E软件对z=8的渐开线少齿数齿轮进行精确地参数化建模,并借助ANSYS有限元软件对其进行了模态分析和扩展模态,得到了5阶固有频率、振型和应力、应变云图.通过研究分析结果,发现了5阶振型的特点,位移、应力和应变的变化规律,提出在动态设计时的几点建议,为渐开线少齿数齿轮传动的合理设计、减少振动和噪音等方面奠定了理论基础.     

少齿数齿轮轴极惯性矩计算

介绍了少齿数齿轮轴的结构特点和少齿数齿轮参数与几何尺寸。依据材料力学中极惯性矩的概念,采用叠加方法,提出了精确计算少齿数齿轮轴极惯性矩的新方法,为研究少齿数齿轮轴的强度、刚度和进一步优化少齿数齿轮副设计参数提供了重要依据。     

少齿数齿轮扭转分析

通过对少齿数齿轮结构和失效形式的分析,针对其主要存在的扭转失效问题,从有限元分析和试验两个方面对少齿数齿轮的扭转刚强度进行了研究。基于APDL语言采用自底向上的建模技术,建立了齿数为2的少齿数齿轮精确模型,并通过施加正反扭矩载荷使用ANSYS软件对其进行了有限元分析;采用RNJ-1000微机控制电子扭转试验机对齿数为2和齿数为3的少齿数齿轮进行扭转试验。得出少齿数齿轮在受扭过程中的一些变形规律,分析了其破坏情况,为少齿数齿轮传动的设计和进一步研究提供理论依据。     

少齿数齿轮的弯扭变形计算

齿数少于7的齿轮轴刚度较差,设计和传动中需要考虑其较大的弯曲和扭转变形。为获取少齿数齿轮轴弯扭变形的计算方法,建立了具有切向和径向变位的小齿轮的端面齿廓模型,得到了齿轮轴弯扭变形当量直径的计算公式。考虑到大螺旋角对齿轮轴弯扭变形的影响,借助有限元计算分析,分别得到了螺旋角对齿轮轴的弯曲和扭转扭变形影响系数。以齿轮轴当量直径、螺旋角影响系数为主要参数,实现了一定精度的少齿数齿轮轴弯扭变形的简化计算。     

热处理及加工定位方式对鼓形齿轮轴加工的影响研究

小模数少齿数大螺旋角齿向鼓形齿轮轴属特型鼓形齿轮轴,其加工精度要求高,有别于一般齿轮轴,国内较为少见。分析研究了热处理及加工定位方式等对鼓形齿轮轴加工的影响,通过改进感应淬火条件及滚齿定位方式等,在特型鼓形齿轮轴加工上取得了较好效果。     

汽车变速箱齿轮轴的模态优化分析

汽车变速箱是齿轮、齿轮轴、轴承和箱体等组成的机械结构,在内部和外部激励作用下将产生机械振动。当激励的频率在结构固有频率附近时,将使箱体产生振动。齿轮轴是变速箱的关键传动部件,为了提高某汽车变速箱输入齿轮轴的前六阶固有频率,应用参数化建模方法和CAE软件对齿轮轴进行模态分析,获得其固有频率和振型,然后基于集成优化平台,采用自适应模拟退火算法对齿轮轴的轴颈直径进行优化设计。最终提高了齿轮轴的低阶固有频率,避免了发生共振,减少了齿轮轴的振动和噪声,并实现了设计优化过程的自动化。     

用有限元法求解减速机齿轮轴临界转速

通过有限元建模方法，运用 ansys 中 lanzcos 方法对齿轮轴进行模态分析，得到减速机齿轮轴横向振动的固有频率特征，并根据频率结果确定齿轮轴的临界转速。     

少齿数渐开线齿轮三维造型技术研究

介绍了基于Pro/E环境下少齿数齿轮建模的方法,为少齿数齿轮的参数化建模、加工设计和有限元分析奠定了基础。     

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.