齿轮轴校直理论及实验研究

基于弹塑性理论，在研究齿轮轴结构的基础上，提出了确定齿轮轴校直行程的计算方法，经实验验证该计算方法是有效的。     

二重完成超大直径齿轮轴渗碳淬火

日前，中国第二重型机械集团公司（中国二重）顺利完成江苏联峰能源80万t大棒开坯机项目中下齿轮轴渗碳淬火工序。据了解，该轴为中国二重迄今为止直径最大的渗碳淬火齿轮轴。由于该件齿轮轴长度达到3911mm，已接近该公司井式渗碳炉尺寸，用常规方法淬火不行。对此，在技术准备时，中国二重工艺员设计了专用起吊吊耳，以保证淬火起吊安全。     

两种热处理方法对减速机渗碳齿轮轴的影响

对减速机渗碳齿轮轴、通常采用渗碳油淬，表淬再低温回火的热处理方法，而对机械性能有特殊要求的渗碳齿轮轴如何处理较为合理呢？本文采用了渗碳油淬后再加一道高温回火的处理方法，通过这两种热处理方法的分析与比较，以期寻找一种最佳工艺方法，满足设计者的要求。     

重载无空刀槽人字齿轮轴的制造加工工艺探讨

以临钢中板厂Ф750中板轧机人字齿轮轴加工为例，叙述了无空刀槽中硬齿面人字齿轮轴，拟定加工工艺时值得注意的一些问题，用以提高齿轮轴使用寿命和达到其技术要求。     

含有裂纹的齿轮轴动力特性分析与模拟

将裂纹梁理论应用于齿轮轴的动力学研究当中，以轴开放裂纹作为研究对象，对齿轮轴出现裂纹后的动力特性进行了分析模拟，并对裂纹位置和裂纹尺寸等对轴特性的影响进行了深入探讨，指出裂纹发生位置对齿轮轴的振型有着直接的影响，在裂纹发生处振型发生突变，而裂纹尺寸对轴的振型和固有频率都有影响，当出现裂纹后齿轮轴的固有频率发生下降，越是大尺寸的裂纹，轴固有频率越是下落显著。这对齿轮轴的损伤监测和诊断具有重要价值。     

NX环境下齿轮轴的模态分析

针对齿轮轴的结构特点,运用有限元方法建立了齿轮轴的有限元模型,进行了模态分析,给出了齿轮轴的前10阶的固有频率和振型,并对频率和位移响应态进行了分析,指出位移变形最大发生部位,为齿轮轴的优化设计提出建议与改进措施。     

齿轮轴多目标优化分析

针对齿轮轴的共振问题,采用有限元方法对齿轮轴进行分析,得到其低阶固有频率及其振型。以齿轮轴第一阶频率和第二阶频率最大同时齿轮轴质量最小为目标函数,基于Isight集成优化平台,分别采用AMGA算法、NCGA算法和NSGA-Ⅱ算法对齿轮轴的轴颈直径进行优化分析,优化之后齿轮轴的第一阶、第二阶的固有频率分别增大了6.16%和6.13%,都处于其啮合激励频率的范围之外,并且其质量较优化之前也有所降低,因此将会有效避免齿轮轴发生共振。     

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。     

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。     

齿轮轴的齿轮和内花键测绘后的参数推算

介绍了在维修复制某进口汽车齿轮轴时，测绘齿轮和内花键的部分参数后，再对其他的主要参数进行推算的过程，为汽车齿轮轴的设计提供参考。     

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.     

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....     

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.     

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.