计算机模拟齿轮加工

针对渐开线齿轮设计，加工及啮合中难以理解的内容，借助于计算机图形学工具，形象，直观地动态模拟齿轮范成加工及配对啮合时的情况，实践证明它能使学生在短时间内，更有效地掌握齿轮传动的理论与实践内容。     

计算机模拟齿轮加工

针对渐开线齿轮设计、加工及啮合中难以理解的内容 ,借助于计算机图形学工具 ,形象、直观地动态模拟齿轮范成加工及配对啮合时的情况。实践证明它能使学生在短时间内 ,更有效地掌握齿轮传动的理论与实践内容。     

内啮合齿轮传动的设计、加工与测量

齿轮传动以其瞬时传动比恒定、平稳性较高、传动比、速度和传递功率的范围大、效率高和结构紧凑等特点，而得到广泛应用。一般来说，平面圆柱齿轮机构分为外啮合、内啮合和齿轮齿条机构三种。外啮合齿轮传动应用较多，工程技术人员对它的计算、制造和测量都比较熟悉；而对于内啮合齿轮传动，由于接触机会少，尤其对非齿轮行业的工程技术人员来讲，在设计、加工制造时，更容易发生一些问题。下面着重对内啮合圆柱齿轮副的设计、制造工艺和测量等方面作一探讨。组成标准的内啮合圆柱齿轮传动由内齿轮和外齿轮组成，它的外齿轮，即小齿轮；内齿…     

直齿-面齿轮动态啮合力有限元仿真分析

面齿轮的动态啮合力分析是高质量面齿轮传动设计的重要内容。基于面齿轮加工原理和CATIA二次开发方法,得到有限元分析所需的三维几何模型。以接触动力学基本理论为基础,建立合理的有限元分析模型,确定合理的参数,使用ABAQUS软件对面齿轮动态啮合力进行有限元仿真分析与研究,得到面齿轮齿面接触力及齿根弯曲应力在连续啮合过程中的变化规律及转速和负载与面齿轮动态啮合力之间的关联规律。论文工作对高性能面齿轮传动动态性能分析有参考价值。     

面向线切割的微小齿轮传动设计研究

在分析了微小齿轮设计与常规齿轮设计不同的基础上，给出了微小齿轮设计需满足的条件和判断齿轮啮合时是否干涉的算法。应用研究成果，针对电火花线切割加工方式，在所开发的线切割自动编程系统中实现了微小齿轮设计、造型及仿真的功能模块，利用该模块可灵活调整齿轮参数，使设计的齿轮副满足正确啮合和连续传动的条件，并能对齿轮啮合状况进行动态仿真以验证设计结果，提高了微小齿轮设计的效率。     

巴斯噶蜗线型齿轮的啮合特性及数字制造技术研究

根据非圆齿轮啮合原理,对巴斯噶蜗线型齿轮进行啮合特性分析及数字制造技术研究。通过对巴斯噶蜗线型齿轮进行节曲线参数化建模、传动特性及凸凹性分析,验证了这类齿轮传动的可行性;通过对其进行齿形设计、CAM实例计算分析及加工仿真,验证了理论设计方法的正确性和可加工性,为这类齿轮的设计、制造、测量及应用提供较为系统的理论基础。     

加工大直径销齿传动外摆线齿轮用指形铣刀的设计与计算

加工大直径销齿传动外摆线齿轮用指形铣刀的设计与计算洛阳矿山机器厂技术处（４７１０３９）王守平，班跃升销齿传动是一种定轴传动形式，以其代替大尺寸渐开线齿轮传动，具有很大的优越性。外啮合销齿传动齿轮的理论齿廓曲线为外摆线，由于一般设计手册中没有给出加工外...     

渐开线圆柱直齿变位齿轮在齿向倒角后的重合度

为了使大规模加工的齿轮不仅能保证一定的中心距、传动平稳、结构紧凑、使用寿命长、而且还应能使齿轮在啮合传动时,噪音小而又悦耳。因此在齿轮加工时,齿顶圆往往使用负公差。同时为了保证一定的中心距或使啮合齿轮寿命接近、不得不把齿轮设计成变位齿轮。由于相互啮合的齿轮模数相同,所以在齿向倒角时值亦相等。由《机械原理》可知:为保证变位齿轮的无齿侧间隙啮合。其齿轮传动时在节圆上的渐开线函数应满足下式要求:     

渐开线齿轮传动啮合效率及噪声分析

啮合效率是齿轮传动质量好坏的重要评价指标之一,直接决定传动齿轮齿廓磨损程度,研究其理论效率对齿轮设计及传动分析有重要意义。应用切线极坐标法分析了渐开线外啮合齿轮副的啮合过程,以瞬时效率为基础完成了其啮合效率函数的推导,通过在啮合区间上积分得到平均啮合效率(简称啮合效率)的计算公式,研究了摩擦系数及变位设计对齿轮啮合的影响,为齿轮传动装置噪声分析及改进设计提供了理论依据和工程应用参考。     

渐开线齿轮滚齿工艺性分析

要提高变速器齿轮传动的平稳性,降低传递误差,对于齿轮齿形的修形要求越来越高。但是,传动过程的齿轮啮合与滚齿过程的加工啮合性质存在差异,前者为平行轴传动关系,后者为交叉角的蜗轮蜗杆传动关系。而设计齿轮的齿顶和齿根存在非渐开线的齿形修缘,不同的传动关系会导致加工出来的齿形与设计目标不一致。正是基于这一点,提出设计齿轮的滚齿工艺性分析方案,以减少后期设计变更带来的开发成本浪费。     

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.     

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。     

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....     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.