恒流量泵凸轮曲线优化设计

利用接接组合法对胜利油田三采油注聚用的恒流量泵凸轮进行了优化设计。分析了多项式运动规律、摆线运动规律等4种曲线,根据恒流量泵的实际要求,将修正摆线位移方程改为凸轮曲线速度方程,并根据接触应力最小原则又进行了改进。优化后曲线无加速度、跃度突变,有利于提高凸轮使用可靠性。     

恒流量泵凸轮失效原因分析及改进

恒流量凸轮泵是胜利油田三次采油注聚合物的关键设备。但在该泵试用过程中发现，凸轮表面过旱地出现了点蚀、剥落等接触疲劳损伤。为分析凸轮失效原因，首先对在凸轮跟踪观察，记录并描述了凸轮表面疲劳失效的外观现象；然后对失效凸轮作硬度分析和金相分析，并在有限元计算的基础上，以剪应力与凸轮维氏硬度比值为依据，分析凸轮失效原因；最后对凸轮热处理方法进行了改进。     

复杂弧面凸轮曲率和应力分析及其CAD

以旋转矩阵算子和微分几何理论作为数学工具，根据空间曲面啮合原理，探讨了复杂弧面凸轮曲率和接触应力的计算方法，对有关计算公式进行了修正，利用VC＋＋编制了弧面凸轮 曲率和接触应力分析的程序，用计算机分析、绘出了凸轮诱导主曲率的变化曲线，并给出了应用实例。     

复杂弧面凸轮曲率和应力分析及其CAD

以旋转矩阵算子和微分几何理论作为数学工具 ,根据空间曲面啮合原理 ,探讨了复杂弧面凸轮曲率和接触应力的计算方法 ,对有关计算公式进行了修正 ,利用VC ++编制了弧面凸轮曲率和接触应力分析的程序 ,用计算机分析、绘出了凸轮诱导主曲率的变化曲线 ,并给出了应用实例。     

凸轮机构恒流量往复泵动力端设计

新型三缸单作用恒流量往复泵动力端采用特殊的凸轮传动机构取代传统往复泵的曲柄连杆机构,使柱塞产生等加速-等速-等减速组合运动规律,从而使得输出流量与压力无波动,大大提高了往复泵的性能。本文就该泵动力端凸轮机构设计进行了详细阐述,并进一步分析液力端恒流量特性。     

弧面凸轮诱导主曲率与接触应力

推导了弧面凸轮诱导主曲率的计算公式,给出了弧面凸轮接触应力计算力学模型,并探讨了接触应力的计算方法。为复杂弧面凸轮设计分析提供了精确化手段,有利于凸轮机的CAD/CAE/CAM系统的建立。     

凸轮车削恒切削角、恒切削速度研究

在凸轮车削加工过程中 ,切削角与切削速度随加工凸轮轮廓位置不同会发生很大变化 ,直接影响凸轮加工质量与刀具使用寿命。为了解决上述问题 ,本文提出了刀具摆动与主轴变转速的凸轮车削加工方法 ,以实现恒角度与恒速度切削。通过对凸轮车削的运动关系进行分析计算 ,推导出在恒角度与恒速度切削的情况下 ,刀具摆角、机床主轴转速与凸轮转角位置的关系 ,为在实际中应用提供了理论依据     

基于Motion分析的无碳小车凸轮逆向设计方法

全国大学生工程训练综合能力竞赛中，无碳小车凸轮的设计是使小车走出理想轨迹的关键。文中根据分析出的理想轨迹，设计了一套基于SolidWorks Motion软件分析的凸轮逆向设计方法。考虑到小车运动轨迹不能出现曲率突变，首先，基于样条曲线设计了理想轨迹，建模并装配小车逆向分析模型，采用Motion逆向分析出凸轮的理论廓线和实际廓线，对完成的凸轮进行Motion仿真检验。结果表明：该设计方法能够设计出符合精度要求的凸轮。这种凸轮逆向设计方法不仅可以应对基础的环S形轨迹，还可以适用更高难度的混合轨迹及变化的赛题。     

弧面凸轮机构的压力角和曲率分析

以微分几何理论作为数学工具 ,根据空间曲面啮合原理 ,给出了弧面凸轮机构压力角和曲率的计算公式 ,利用VC ++编制了弧面凸轮机构压力角和曲率分析程序。以弧面凸轮机械手中的提升凸轮为例 ,用计算机分析、绘出了凸轮副压力角和诱导主曲率在各种情况下的变化曲线 ,并据此对凸轮副压力角和曲率的变化规律进行了分析与总结。     

基于非圆齿轮驱动的恒流量高阶椭圆凸轮泵设计

凸轮泵是一种结构紧凑、无磨损且适用范围广的高性能容积泵。针对新式椭圆凸轮泵流量脉动大的性能缺陷,提出了基于非圆齿轮变速驱动的脉动平抑方法。在阐明高阶椭圆凸轮泵工作原理的基础上,建立了泵的瞬时流量公式,并分析了转子偏心率、阶数及长半轴长度对瞬时流量的影响;针对大脉动流量的成因,提出了基于非圆齿轮的平抑方案,根据瞬时流量公式反求出平抑用非圆齿轮的传动比,通过留数定理证明了非圆齿轮的封闭性,为该非圆齿轮的设计奠定理论基础。分析结果表明:非圆齿轮变速驱动的高阶椭圆凸轮泵可以实现恒流量输出,平抑齿轮和同步齿轮间的相位角误差是制约流量是否恒定的关键参数。     

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.