细长轴的拉夹车削法

细长轴的拉夹车削法河北邢台王转柱细长轴的车削、方法较多．诸如利用跟刀架车削、专用工具车削等。但它们都有一个共同的特点、就是工件必须用顶尖顶着。因细长轴的长径比较大．刚性较差．受压时极易失稳而弯曲、特别是有横向力作用时更是如此。同时因机床主轴卡盘转动的...     

利用磁力跟刀架减小细长轴车削振动

本文应用自行研制的“磁力刀架”进行了车削细长轴实验研究,考察了细长轴的振动情况.研究表明:该刀架可降低工件振动,工艺系统振动越大,其效果越明显;该刀架的减振效果不随气隙里单调变化,对应工件最小振幅,存在最佳气隙值.     

车削细长轴的装夹方法

车削细长轴时,一般是一端用卡盘夹住,另一端用顶尖顶住,然后进行车削。由于车床卡盘的卡爪钳口不可能与车床的主轴中心线绝对平行。因此,装夹后的细长轴容易成为图1所示的形状,如果细长轴装夹处有些弯曲,则装夹后就会把弯曲部分夹直,从而产生了装夹外应力。所以当松开卡盘的卡爪后,在近卡爪的一端仍会恢复原来的弯曲形状。     

利用磁力跟刀架减小车长轴车削振动

本文应用自行研制的“磁力刀架”进行了车削细长轴实验研究，考察了细长轴的振动情况。研究表明：该刀架可降低工 振动，工艺系统振动越大，其效果越明显；该刀架的减振效果不随气隙呈单调变化，对应工件最小振幅，存在最佳气隙值。     

车削细长轴专用刀架

用普通跟刀架车削细长轴,由于径向切削力而产生振动,影响零件的质量。我们设计了一种车削细长轴专用刀架(见附图)。其特点如下: 1.采用垂直切削方式,径向切削力向     

微型细长轴类零件的车削加工工艺实践探索

本文以某微型细长轴零件为例,针对该零件加工过程中,在受到零件结构、床鞍干涉等因素的影响,无法使用中心架、跟刀架、顶尖进行辅助支撑的情况下,探索如何改善此类零件在车削加工过程中因刚性差、受切削力的作用出现变形和振动的现象。经实践,通过选择合适的毛坯尺寸,合理安排加工顺序,优化刀具几何形状,采用分层、分段组合加工法及挡屑装置等加工工艺,可有效增强微型细长轴类零件在车削加工中的刚性,有效减少因受力而产生的变形和振动。     

细长轴超声椭圆振动辅助车削试验

设计了铝合金细长轴超声椭圆振动辅助车削试验,测量了不同超声波电压下的刀具振幅。分析了铝合金细长轴超声振动辅助车削切削力变化规律,开展了普通车削与超声椭圆振动辅助车削单因素对比试验,对比了两种不同加工方法对切削力及细长轴不同区域表面粗糙度。试验结果表明:在相同切削参数条件下,超声椭圆振动辅助车削三个方向的切削力均小于普通车削切削力,并且随着振幅的增加切削力进一步降低。两种加工方式下细长轴的中间区域表面粗糙度均比两端差,但超声椭圆振动车削沿细长轴长度方向的表面粗糙度的均匀一致性优于普通车削。超声椭圆振动车削加工后的表面纹路较普通车削均匀缜密,且断屑效果优于普通车削,普通车削形成的切屑为连续切屑,切屑缠绕严重,而超声椭圆振动辅助车削的切屑形状为断续切屑,随着振幅的增大断屑效果提高。     

细长轴超声波辅助振动车削试验研究

在细长轴车削加工过程中,切削力是影响加工质量的重要因素之一。由于超声波辅助振动车削加工可大幅度降低切削力,因此,本文通过超声辅助车削加工细长轴的试验研究了超声辅助车削对于改善加工质量的作用。研究结果表明,超声辅助振动车削不仅可以改善细长轴表面粗糙度,还能够有限度地降低切削变形。     

细长轴车削加工误差的分析

针对细长轴的车削加工。分别对在一端卡盘夹紧、一端顶尖支承及两端顶尖支承的装夹条件下车削加工时的变形进行力学分析。建立在切削力作用下产生弯曲变形的解析模型。算侧表明：逆向车削时轴的弯曲变形以及加工误差远小于同等条件下正向车削的变形和误差。     

提高细长件表面质量的加工新法

本文应用自行研制的“磁力跟刀架”在ＣＡＤ６１４０型普通车床上车削细长轴，考察了工伯表面粗度Ｒａ值的变化规律，研究表明：由于该刀架显著提高了工艺系统刚度、减小了振动，使工件表面粗糙度Ｒａ值明显减小，另外，由于利用该刀架可实现高速车削，从而使工件表面粗糙度进一步减小，生产率大大提高。     

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.     

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.