基于SolidWorks Simulation的定位管支撑本体静态及疲劳分析研究

针对柔性接触网中腕臂装置的工作特点,选取定位管支撑本体作为研究分析对象,根据定位管支撑本体的几何物理模型,在SolidWorks Simulation中建立了有限元模型,选取了5个幅值加载载荷,用2种加载方式对该本体进行了静力学分析,并在正交加载的基础上,为该本体定义疲劳曲线（S-N曲线）,对该本体进行了LR=0和LR=-1两种加载情况的疲劳分析。在静应力分析中研究分析了不同载荷幅值和不同加载方式对定位管支撑本体的应力分布和屈服区域分布的影响;在疲劳分析中,研究分析了定位管支撑在两种加载情况下疲劳生命周期的分布规律。在理论上对以后进行其它同类型管类支撑件的设计和可靠性分析有一定的参考价值。     

可调整式“一面两销”定位装置的应用

“一面两销”定位是机械加工中工件与夹具、夹具与机床定位方式中最常用的一种形式,介绍了一种可调整式“一面两销”定位装置的设计特点,通过定位销基座的方式完成定位销和机床夹具本体的连接,同时具有位置可调性,从而满足定位销的位置优化。相对于固定式“一面两销”定位装置,在专用夹具设计应用中具有较大的便捷性、优越性和兼容性,能够针对夹具定位误差进行补偿校正,有效地消除各种定位误差带来误差影响,提高一面两销定位精度,大大提高工件加工的位置精度。     

简易双轴立铣头装置设计与应用

针对飞锤工件基准定位面的加工问题,设计制造了一种双轴立铣头装置。一次铣削可完成两个工件基准面的加工。该装置结构简单、安装调整便捷。使用结果表明该装置在满足加工质量的同时,极大地缩短了产品的加工时间,降低了生产成本,提高了加工效率。     

基于磁流变液辅助支撑的弱刚度零件铣削加工研究

设计了一套基于磁流变液特性的自适应式柔性辅助支承装置,可用于提高复杂曲面弱刚度零件的加工精度,通过Comsol利用有限元法进行装置磁场仿真,确定其磁场强度大小,建立基于磁流变效应的弱刚度工件铣削加工与夹具系统装夹定位模型,对辅助支撑作用下的定位约束模型进行分析,计算静态下工件变形量,研究装置对工件加工质量的影响。搭建基于磁流变辅助支承铣削加工试验平台,在不同电流参数的条件下进行弱刚度零件铣削加工,使用Labview平台采集系统对切削信号数据进行采集分析,并测量铣削加工表面粗糙度,结果表明,磁流变辅助支承作用下,弱刚度工件表面相较于无支撑状态振动幅度相应降低了46.9%～75.7%,表面粗糙度约降低69.89%～80.61%。     

汽车主模型薄壁件加工防变形夹具设计与研究

针对汽车检测工具主模型薄壁部分切削加工过程中工件容易变形的问题,设计了薄壁件加工防变形夹具,利用浮动的辅助支撑杆对工件进行支撑,可以在磁流变液浮力的作用下与工件表面自适应贴合。设计了真空吸盘和定位装置对工件夹紧与定位,滑动定位装置可实现夹具在空间区域进行定位,采用真空吸盘装置的夹紧方案可以快速更换加工工件,不影响表面加工质量且方便稳定。柔性体现在夹具能够自适应调整以适用于不同类型主模型薄壁件的切削加工,从而节省夹具的制造成本。利用计算机辅助软件算出夹紧点的合理位置,能保证工件在加工中不产生位移和变形;利用磁流变液锁紧装置可快速改变辅助支撑杆的松紧状态;提高了工件的装夹效率,节省工时,实现加工要求。     

一种异形工件的定位装置

针对一种形状特殊、难以装夹定位的异形工件,为满足铣削加工过程中高精度、降低磨损、易于安装的要求,提出了一种新型专用机床对该工件进行装夹。介绍了定位装置的结构设计、工作原理,并给出了合理的定位方案。该定位装置可以有效降低对工件定位面的磨损,保障机床的加工精度,其结构简单,可降低装配、调试人员的劳动强度。     

红岩汽车后桥主减壳某工序夹具设计

根据工序特点,夹具设计采用一面两销定位原理对工件定位。由于工件较重,加工部位多,在夹紧工件方面采用液压夹紧及辅助支撑方式。工件上下场采用抽屉式方式进行,极大地提高了上下工件的效率,减轻了操作者劳动强度。     

某弓锯床的自动送料装置设计与应用

针对某弓锯床下料效率低、下料精度差和劳动强度大的问题,设计了一款弓锯床的自动送料装置,该装置能实现气动夹紧工件、轧辊支撑工件及步进电动机自动输送工件的功能。对其进行了整体结构设计,关键零/部件选型计算。通过对水平夹紧机构进行有限元分析,进一步来验证结构设计的合理性,最终做出实物样机。经过调试,自动送料装置的送料效果达到预期目标,该装置的设计与应用对废旧设备进行改造有一定的参考和实用意义。     

非圆旋转工件随动支撑装置及其运动分析

针对非圆弱刚性工件旋转加工必须安装中间随动支撑的要求,设计了一种"V"型支撑装置,研究了带有负曲率的非圆截面CAD图形驱动自动生成支撑臂瞬态位移的计算方法,并据此编写了支撑装置运动控制程序,搭建了试验系统。实验证明该系统完全能够保证对任意非圆工件旋转随动支撑的连续性、实时性与平稳性。     

基于MRF柔性辅助支撑的弱刚性零件铣削加工

设计了一套基于磁流变液的柔性辅助支撑装置,用于提高弱刚性零件的加工精度.利用有限元方法通过Comsol软件对装置磁感应强度进行仿真,研究其提供的支撑力大小,运用工程力学知识对加工工件进行力学分析、理论变形量计算以及对加工工件进行有限元加工变形仿真,研究不同加载电流状态下磁流变液辅助支撑装置对加工工件变形情况的影响.最后...     

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...     

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.     

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.     

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.     

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....     

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.