基于摇杆滑块机构自动砂轮切割机的设计与研究

浇口切割是熔模精密铸造技术的后处理工序,采用手动切割机切割,劳动强度大,生产效率低.根据工程实际中的生产需求,对切割机的外观和机械结构进行设计,基于摇杆滑块机构原理对切割机构进行优化.采用SolidWorks对机械结构进行三维建模,利用Motion验证改进切割机构的可靠性,使用Simulation对关键部件进行有限元分...     

小型金相试样切割机机械部分的设计

小型自动化金相试样切割机由机械部分和控制部分组成,文中针对机械结构部分进行设计。设计的小型金相试样切割机机械部分由切割机构、进给机构、夹具、机体和冷却系统组成。采用切割系统固定不动、试样进给的切割方式工作。切割机构采用三相变速异步电动机变速驱动,以简化机械结构并实现切割速度可调。三个方向的进给采用步进电机驱动滚珠丝杠来实现。夹具采用了螺旋夹紧机构。     

活塞环金相试样切割机双轮操作移动式升降台设计

活塞环金相试样切割机由机械部分和控制部分组成,机械部分由砂轮片切割机构、进给机构、夹具、机体和冷却系统组成,采用砂轮片切割机构固定不动,夹具内的活塞环金相试样前后、上下进给的切割方式工作,本文针对进给结构、夹具进行设计,结构型式为双轮手动控制的前后移动式升降台。     

91I床整机系统振动特性分析

机床作为生产的重要工具和设备,其加工性能与其动态性能紧密相关,并将直接影响所加工零件的精度。随着现代设计方法的广泛运用,对机床进行动态特性分析,用动态设计取代静态设计已成为机床设计发展的必然趋势。1．模态分析的基本理论振动现象是机械结构经常需要面对的问题之一,由于振动会造成结构的共振或疲劳,从而破坏结构,所以必须通过模态分析了解模型的各阶固有频率和振型,避免在实际工况中因共振因素造成结构的损坏。     

基于两步法的饮料塑料防盗瓶盖切割机设计

为了解决防盗瓶盖在一次注塑成型中存在的瓶盖主体与防盗环产生粘连及制盖模具结构庞大的问题。将注塑与机械切割相结合的两步法技术应用到制盖工艺中。开展了采用机械切割的方法切割防盗环的分析,建立了切割机与瓶盖防盗环之间的关系,进行了切割机的设计、制造工作,并提出了在瓶盖注塑成型后加一道切割工艺生成防盗环的制盖方法,最后,对切割机进行了瓶盖的切割试验。试验结果表明,与一次注塑成型的防盗瓶盖相比,该方法不仅解决了防盗环的粘连问题,同时去除了制盖模具中的抽芯机构,简化了模具结构,使模具的制盖产量提高一倍以上。     

往复式压缩机管道振动及减振措施

长期以来,管道振动的问题,曾给压缩机用户造成极大的困扰。这是由于管道振动会导致管道和支架的疲劳损坏,建筑物的振动及噪声等问题。 造成管道振动的原因通常有两个:一个是机器动力平衡性能不好或基础设计不良;另一个是气流脉动。实践表明,多数的振动为气流脉动所引起。     

火焰切割机及其凸轮机构的设计与仿真

在圆柱壳体上切割大直径偏心圆孔和变角度坡口一直是机械加工中的一个难题。因此,研究一种结构简单,价格低廉,精度及自动化程度都比较高,可以完成直径大于1.2 m的相贯线曲线切割的火焰切割机具有十分重要的意义。作者在研究国内外类似设备及技术的基础上,提出了一种新的圆柱面大直径孔火焰切割机的设计方案。借助数学中的坐标系平移变换矩阵,导出了相贯线轨迹方程,完成了火焰切割机凸轮机构的数字化设计与运动仿真,验证了所设计机构的正确性和良好的动态特性。     

管件相贯线等离子切割装置的设计

随着城市化建设和汽车行业的发展,栏杆类、管道类的器材使用量剧增,由于栏杆、管道等相接是采用相贯线切口,所以需要对管件进行相贯线切割加工。目前,相贯线切割机存在一些问题,如数控类型成本高、样板靠模等工艺落后。本文设计了一款能对小于300mm的不同管径的相贯线进行切割,实现快速且低耗要求的相贯线辅助切割装置,主要结构由切割执行机构、工件夹持机构组成,控制系统由12V适配器、步进电机驱动器、AT89C52单片机、降压模块、电机模块组成。该装置适用范围广、成本低,更能有效提高管件切割效率。     

轻型桥式起重机主梁焊缝疲劳寿命影响因素分析

轻型桥式起重机采用先进的优化设计理念,在保证主梁金属结构满足强度、刚度、稳定性的前提下实现减重以降低成本。主梁的损坏大部分是由于承载焊缝的疲劳失效引起,文中以等效结构应力法焊趾疲劳理论为基础,采取数值模拟方法对轻量化主梁焊缝进行疲劳寿命分析,对影响其寿命的因素进行了规律性研究,并推荐主梁承载焊缝的最优形式,研究结果对于箱形梁承载焊缝的可靠性设计具有一定的参考价值。     

一种新型可调式切割机的研究设计

为解决普通切割机只能依靠操作人员的主观感觉来控制切割深度的问题,设计了一种新型可调式切割机,采用附加装置的设计思想,在普通切割机刀片两侧加装定程调节装置和进给限位装置,从而实现了可控制深度的切割,介绍了其机构设计原理、整体结构和性能参数。新型切割机可以让切割者在设定的深度下毫无顾虑的切割,提高效率。     

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.     

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....     

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.