薄壁齿轮车削的创新加工工艺设计

薄壁零件具有质量轻、节约材料、结构紧凑等特点,但刚性差、强度弱,不仅装夹容易变形,而且在车削中产生的切削力和切削热都会使零件变形.针对薄壁齿轮零件厚度较薄、加工精度要求较高、加工过程中容易产生变形等问题,对加工工艺进行改进,解决工件的变形问题,保证了零件的加工质量.     

薄壁铝制零件加工工艺研究

薄壁铝制零件在数控加工中容易发生零件变形、折断现象。文中利用因果图分析出零件变形的可能影响因素,找出主要原因是加工工艺不合理和零件装夹方式不合理,然后通过理论分析修改装夹方式、调整加工工艺。薄壁铝制零件的加工合格率明显得到了提升。     

一种铝制异形薄壁零件的加工方法

针对某铝制异形薄壁零件加工过程中易造成零件变形的问题,设计了相应的磨削工装,配合合理的加工工艺来减少加工变形,从而得到各项尺寸都符合要求的成品。     

中间连接轴轴承座数控加工工艺分析

由于薄壁零件在加工过程中受到夹紧力不均匀而使工件产生变形等问题。因此，要针对上述问题选择合理的工艺方案,这是保证薄壁零件加工质量的关键。本文讨论的中间连接轴轴承座零件在实际加工过程中,由于振动容易引起变形,影响工件的尺寸精度、形位精度和表面粗糙度，因此提出了防止中间连接轴轴承座零件变形的新工艺及程序。     

不锈钢薄壁螺母零件加工工艺设计

针对薄壁螺母零件刚性差、加工过程中容易产生变形、加工精度不高等问题,在仔细分析零件结构及加工要求的基础上,对加工工艺进行改进,重新设计工装,解决了工件的变形问题,克服了加工难点,保证了零件的加工品质。     

数控铣床易变形薄壁零件的加工

采用传统加工工艺加工薄壁零件,容易产生零件的报废,通过对装夹方式、工艺工序、刀具选择等几个方面的优化,可以有效解决薄壁零件加工过程中出现的变形,并保证工件对称度要求,为类似零件的加工提供方法借鉴。     

薄壁腔体类零件加工变形问题工艺研究

薄壁腔体零件的铣削加工变形是影响产品加工质量的重要因素。在微波测试仪器中广泛采用薄壁腔体类零件,此类零件一般都具有结构复杂、加工难度大等特点,而且在加工过程中容易产生较大的变形,难以保证加工精度和表面质量。在工艺研究中,采用粗、精铣削加工分离的工艺流程,低温去应力退火的热处理方式以及采用“无应力”装夹方式等工艺方法的改进,减小零件在铣削加工过程中的变形,从而提高了零件的加工精度和表面质量。     

一种铝制空腔轮状零件的加工方法

某包装轮为典型铝制薄壁空腔件,加工时容易产生较大变形,导致零件报废。文中设计合理的加工工艺及相应工装来减少加工变形,从而得到各项尺寸都符合要求的成品。     

大口径薄壁筒类零件车削工艺研究

针对薄壁筒类零件加工过程极易产生变形的问题,分析了薄壁衬筒在车削中的加工难点,并制定了满足其加工精度要求的车削工艺方案与具体工艺流程,提高了产品合格率,为薄壁筒类零件加工过程的变形控制提供了有效的工艺参考。     

薄壁铸造铝合金壳体加工变形控制研究

根据薄壁壳体整体结构特征,对其加工工艺进行分析,确定加工工艺方案;基于整体工艺方案,充分考虑零件加工过程中装夹定位,以最大程度减少零件加工过程中的变形问题;通过选取合适的加工刀具及加工参数,减少零件加工过程中因切削而导致的变形问题;其他控制措施还包括采用增加辅助支撑等方式,减少零件加工过程中的震颤问题,从而控制零件变形。     

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.