卷板机改制圆弧成型机的方法

针对通风机及相关设备在加工法兰、圆筒翻边与旋压弧面成型工艺,介绍了在卷板机的基础上,改制多功能圆弧成型机的方法,解决了一些中小风机制造厂工艺技术上的难题,降低了制造成本,提高了生产效率.     

超半球壳体多道次拉深旋压工艺研究

针对1060超半球壳体基于板坯多道次拉深旋压进行成形性分析,提出两模法和两轮法的旋压成形试验方案,并设计不同旋压试验方案的芯模和旋轮工装.通过MC2000型数控录返旋压机,分别采用R13、R20和R25、R8不同圆角半径的圆弧式旋轮对1060板坯进行两模法和两轮法的多道次拉深旋压成形试验.两模法旋压毛坯件的凸缘边减薄严重,成形效果差;两轮法旋压采用R25旋轮4道次快速进给,R8旋轮4道次中低速精整旋压的旋压工艺,其旋压件贴模度高,成形效果好.试验结果表明:两轮法旋压工艺能实现板坯经多道次拉深旋压成形为超半球壳体.通过降低芯模转速,调整进给比和降低道次减薄率,可以消除旋压成形过程中出现的反挤、波纹和起皮等缺陷.     

变螺距变槽深变槽宽螺杆数控加工的开发

成型拉链机中的成型螺杆模具,其关键部件变螺距变槽深变槽宽的异型螺杆是加工的难点.本文通过分析变螺距、变槽深、变槽宽螺杆的成形原理,建立了该类螺杆的参数化数学模型,开发出变螺距、变槽深、变槽宽螺杆的专门数控加工程序.在数控车床上实现螺距、槽深、槽宽三者同步变化的数控加工控制功能,满足拉链成型机及各种挤塑机中异型螺杆的数控加工要求,为该类异型螺杆的设计、加工提供了可行性的方法.     

滚旋压加工异型管的数控化应用

介绍了应用数控技术的优越性,根据滚旋压异型管零件加工运动的构成和实现要素,进行了特殊形式的数控改造。利用伺服电动机直接控制主动滚轮和从动滚轮的旋转,将数控加工的直线运动转换为旋转运动来进行异型管零件的滚旋压加工控制。阐述了应用于滚旋压加工的原理、控制与实现,分析了零件弯曲变形的规律,以及各相关因素对匀变速运动的影响。结果表明,滚旋压加工异型管的数控化研究应用,在实际应用中收到了良好的效果,拓展了数控技术在实际中的应用。     

一种用于锥筒形零件的简易旋压专用机床的改制

一些锥形回转体薄壁零件,传统的方法用钣金展开下料后用相应的模坯上整形后再焊接而成,费工又不美观.本次专用机床改制是用旧C6136A车床床头,增加旋压装置、液压装置及电气和液压控制装置改制成一种用于锥筒形零件的简易旋压专用机床.通过对旋压加工工艺、旋压机床的机械结构、液压及电气控制及旋压机床的使用及工艺分析,制作一种实用可行的旋压设备,一次旋压成型,不需焊接,提高产品生产效率及质量,降低生产成本.类似形状的锥形回转体薄壁零件加工,只需更换模具及调整旋压装置移动的角度.     

发动机多楔皮带轮旋压工艺的研究

针对发动机多楔皮带轮大变形成型工艺问题,对塑性变形理论、多楔皮带轮材料本构模型及材料间摩擦类型等方面进行了阐述,对多楔皮带轮旋压过程中的毛坯、旋轮、芯模、尾顶进行了三维建模与装配,并对各零件之间的相对运动进行了分析。根据皮带轮楔型结构特征,基于Deform软件和刚塑性模型,提出了采用冲压和4道旋压工艺的多楔皮带轮成型方案。进行了有限元数值仿真,分析了各道旋压工序的实时动态应力应变状态及成型缺陷。通过模具试制和实际加工,对冲压和4道旋压工艺的方案进行了验证。研究结果表明:多楔带的齿槽和齿状填充饱满,加工的工件外形尺寸与零件图基本吻合,成型效果较好;该旋压工艺方案能较好完成多楔皮带轮成型加工。     

肉脯成型机设技

肉脯是中国传统肉制品.至今加工肉脯的关键工艺--铺片成型仍采用手工作业.肉脯成型机研制成功为机械化生产肉脯提供了设备,该机铺片成型效率是手工加工的7～8倍,它适合各种肉糜,泥类物料片状制品加工.     

电火花轮廓加工

针对日本SODICK公司A35R-E电火花成型机的成型轮廓加工特征,应用范围,加工性能以及选用原则进行了论述,其目的在于介绍轮廓加工在电火花机床上的应用情况,为更好的利用和发挥数控电火花成型机床在生产中的广泛应用,起到促进作用。     

罩壳零件在普通车床上的旋压加工

根据旋压成型的原理,在普通车床上,通过设计特殊的刀具以及合理的加工步骤,实现了软铝材料罩壳零件的旋压成型加工。加工结果表明,与冲压成型和车削成型相比,该方法对于小批量罩壳零件加工,具有效率高,成本低的特点。     

钛合金薄壁零件旋压工艺

介绍了钛合金薄壁零件旋压成型加工过程。针对钛合金材料旋压成型困难问题,经反复试验,通过高温改变钛合金组织平衡、控制变形的温度、变形速度,采用多道引申旋压等参数的选择,最后稳定尺寸的热处理技术解决了钛合金薄壁零件旋压的难题。该方法提高了加工质量,稳定加工尺寸,达到了降低成本的目的。     

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。     

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.