深孔加工负压排屑系统的优化设计仿真研究

在机械制造业中,孔加工是一大难点,深孔加工又是最困难的一种。研究负压排屑系统对深孔加工的排屑这一难题有重要意义,尤其在准干式深孔加工中。通过对已有深孔钻削负压系统工作原理的理论分析,且对深孔加工负压系统中的流体建立了数学模型,文中提出一种新型高效的双曲面负压系统,并利用Fluent软件进行流体运动的压力场和速度场仿真分析。通过对比负压系统的总压速度云图、总压和速度XY散点图,研究结果表明:双曲面结构比锥面结构的负压效果更明显,试验结果与理论分析相吻合。     

一种新型的深孔负压装置研究

通过对现有DF深孔钻削系统的结构及工作原理的理论分析,研究新型双锥面负压射流结构、负压机理及排屑特性,提供一种排屑能力更强、工艺性更好、加工精度和生产效率更高、孔径实用范围更广的新型深孔双锥面负压装备,应用于ZK2138深孔钻床,结合理论分析,进行正交化设计试验,最终确定新型双锥面负压射流通道的合理几何参数.     

深孔钻削双锥面负压系统研究

通过对现有DF深孔钻削系统的结构及工作原理的理论分析,研究新型双锥面负压射流结构、负压机理及排屑特性,提供一种排屑能力更强、工艺性更好、加工精度和生产效率更高、孔径实用范围更广的新型深孔钻削双锥面负压装备,应用于ZK2138深孔钻床,结合理论分析,进行正交化设计试验,最终确定新型双锥面负压射流通道的合理几何参数.     

深孔加工可转动负压抽屑装置的研究与设计

针对大尺寸和形状复杂的零件,在深孔加工过程中,采用传统的工件转动,刀具进给已经不能满足加工需求。采用刀具旋转进给,工件静止的加工工艺在现代深孔加工技术中显得很有必要。通过对现有DF深孔钻削系统的结构及其工作原理进行理论分析,对负压抽屑装置进行改进,设计出可转动负压抽屑装置,从而更好地满足实际生产的需要。     

深孔加工关键技术研究

分析了航空航天制造业中的一项关键技术——深孔加工工艺技术的特点以及影响深孔加工的各种因素。应用高效抽屑技术和机电一体化技术，研制推出了新型深孔加工技术及其装置——可调式高效负压抽屑装置和电磁式过载保护装置。通过试验证明，进一步优化了负压抽屑装置结构设计，从而使排屑更为流畅，大大提高了深孔加工的精度和生产效率。     

深孔钻削双锥面负压排屑系统数值模拟与试验研究

以深孔加工单锥面负压排屑系统为设计依据,根据流体力学理论设计双锥面深孔负压排屑系统,并建立流体力学模型与数学模型.利用计算流体力学(FLUENT)技术,对一系列不同负压结构进行了数值模拟.模拟过程入口与出口均采用压力边界条件.分析排屑通道压力与速度变化曲线,得出排屑通道内流体的压力与速度变化规律.通过与实验结果进行对照发现,射流喷嘴大小以及角度是影响深孔排屑的重要因素,而且与单锥面负压排屑系统相比,双锥面负压抽屑效能明显增强.     

准干式深孔加工系统构建

综合多种现代绿色冷却润滑的优点,并结合深孔加工的特点,采用以油膜附水滴为冷却润滑介质,结合新型的负压抽屑装置和复合喷雾装置,构成准干式深孔加工系统.准干式深孔加工系统变传统的浇注式深孔加工为新型环保的半干加工,实现深孔加工的准干式切削,在深孔加工的环境污染和能源损耗的问题上有突破性进展.系统设计的主要部分包括复合喷雾装置设计、负压抽屑装置设计、绿色切削液研制以及MOL技术应用.     

井下工具深孔内壁加工系统及试验研究

针对石油钻采、测井等领域井下工具深孔类零件内壁盲孔及键槽的加工难点,设计深孔内壁专用加工装置,并介绍其工作原理;设计与该加工装置配套的深孔内壁加工系统,为加工装置提供装载平台。以TC4钛合金深孔零件为试验对象进行深孔内壁盲孔及键槽的试验验证,分析切削参数对加工质量的影响,验证了深孔内壁加工系统的有效性,为井下工具深孔内壁盲孔及键槽的高效、精密加工提供一种新方法。     

旋转DF系统的多结构参数建模及结构设计

针对深孔加工中排屑难、效率低的问题,设计出一种具有刀具旋转功能的DF钻削系统。基于流体力学理论建立了深孔机床DF系统的多结构参数数学模型,揭示了主要结构参数对负压抽屑效果的影响规律,获取了最佳的参数组合。进一步地,对现有旋转DF系统进行了结构完善及参数优化。研究结果为深孔机床抽屑装置的优化设计提供了可借鉴的方法。     

亚干式深孔加工刀具技术

结合干式切削和深孔加工的特点,提出一种亚干式深孔加工解决方案,介绍了亚干式深孔加工系统以及深孔刀具的结构设计。通过切削试验,确定了适用的刀片材料,并对干、湿两种加工方式下刀具的切削性能进行了对比分析,设计了适用于亚干式深孔加工的切削刀具。     

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.