钛合金车削中的低温油膜水滴冷却润滑技术

简述了低温油膜水滴(cryogenic Oils on Water,低温OoW)切削液的冷却润滑原理。通过测量常规浇注、低温冷风和低温OoW切削液三种冷却润滑方式下切削钛合金的切削温度、刀具寿命和工件表面质量的对比试验,研究低温OoW切削液的冷却润滑性能。试验结果表明,低温OoW切削液具有良好的冷却润滑效果,能有效降低切削温度、提高刀具寿命和降低表面粗糙度值,且在切削速度提高时,对比效果更为明显。     

微量油膜附水滴切削40Cr合金结构钢试验研究

简述了油膜附水滴(oils on water,OoW)切削液的冷却润滑原理。通过干切削、常规浇注乳化液和OoW切削液三种冷却润滑方式,切削40Cr合金结构钢的切削力以及工件表面粗糙度的对比试验,研究OoW切削液的冷却润滑性能。试验结果表明,OoW切削液能有效减小切削力和表面粗糙度值。     

乳化液与油膜附水滴切削液的对比试验研究

简述了油膜附水滴(Oils on Water,OoW)切削液的冷却润滑原理。为了研究油膜附水滴切削液和乳化液在切削45钢过程中的冷却和润滑性能,通过对浇注乳化液和OoW切削液两种冷却润滑方式下切削45钢的切削力、工件表面粗糙度的试验进行比较,分析两种切削液的冷却润滑性能。试验结果表明,使用OoW进行切削润滑,能够降低切削加工过程的切削力和工件表面粗糙度,与采用乳化液相比具有明显优势,为实际加工过程的切削参数选择及润滑液选择提供了重要参考。     

微量油膜附水滴切削液加工对切削力影响的试验研究

为探索研究微量油膜附水滴(OoW)切削液在车削中对切削力的影响,选出较适宜的切削用量,通过正交试验方案,分别研究在干切削和OoW切削两种不同加工方式下,切削速度、进给量和背吃刀量等切削参数对车削45#碳素结构钢时主切削力的影响。经多元线性回归处理,建立切削力经验公式。结果表明:在使用OoW切削液润滑的情况下,主切削力变化范围较大,但采用较高切削速度、较低进给量、较大的背吃刀量时,主切削力较干切削时有明显下降。     

微量油膜附水滴不同喷射方向切削效果试验研究

利用油膜附水滴(OoW)切削液进行切削试验研究,并采用不同喷射角度进行喷射冷却润滑.试验结果表明,同干切削、乳化液冷却润滑加工相比,微量油膜附水滴能够降低切削力的产生,对后刀面和刀具侧面进行喷射切削效果更好;微量油膜附水滴切削液能够显著降低加工表面的粗糙度.     

钛合金绿色切削加工工艺优化研究

以Ti6Al4V钛合金为研究对象,采用含交互作用的正交试验方法,研究分析了冷却方式(传统切削液、微量润滑MQL和油膜附水滴OoW)、切削转速、进给速度和切削深度四个因素对铣削过程中切削力、表面粗糙度和刀具磨损的影响。结果表明,具有良好润滑性能的MQL技术切削合力比OoW总体更低;采用MQL和传统冷却液的粗糙度接近且优于OoW。冷却方式和进给速度对切削合力的影响程度高于冷却方式与其他切削参数交互作用;冷却方式和切削转速的交互作用对粗糙度的影响程度最高。MQL绿色冷却因良好的润滑效果,相比OoW能更好地抑制后刀面磨损,有望取代传统冷却液进行钛合金的绿色加工。     

微量油膜附水滴切削试验研究

论述微量油膜附水滴(Oil on Water,OoW)加工液发生原理和冷却润滑特点.针对该切削液的冷却润滑特点进行车削试验研究,并在同干切削和乳化液冷却润滑加工方式对比研究的基础上,通过对切削力、平均摩擦因数和切屑形态的研究分析,揭示出微量油膜附水滴具有良好的冷却润滑效果.     

45钢切削试验研究

简单介绍了几种新型的绿色制造技术,分别是干切削、低温冷风切削以及油膜附水滴切削,并阐述了油膜附水滴(Oils on Water,OoW)切削液的作用机理。基于干切削、常温浇注乳化液和油膜附水滴这三种不同的冷却润滑方式,分析和比较了45碳素结构钢所受到的切削力以及刀具后刀面磨损状况,得到的结果表明:在相同的外界条件下,三种冷却润滑方式中微量油膜水滴具有很明显的优越性,不但切削力最小,同时可以减缓后刀面的磨损。     

基于田口方法的车削45钢参数优化分析

为了分析油膜附水滴切削液(OoW)润滑时,影响切削力的关键因素以及最优的切削加工参数。运用田口实验方法,对45钢进行切削实验研究。运用方差分析方法和静态信噪比对采集的实验结果进行数据处理及分析。分析结果表明:背吃刀量ap、进给量f对切削力的变化有着高度显著性影响,切削速度V的改变对切削力有着显著性影响。通过田口方法的分析得到的最优切削参数为切深0.6mm,进给量0.08mm/r,转速120m/min,为今后实际工业生产中切削参数的优化提供了重要参考。     

基于MQL的切削加工技术应用

在金属切削加工过程中,切削液发挥着冷却、润滑、排屑和防锈等作用,但其排放会对环境造成严重污染。微量润滑技术(MQL)是将压缩气体与微量润滑油混合汽化后喷射到加工区域,可代替传统切削液,在刀具与工件间的加工部位形成有效润滑,减缓刀具磨损。作为新兴的绿色清洁切削加工技术,微量润滑技术具有广阔应用前景。本文介绍了切削加工机理和切削液在切削加工中的作用,通过对比微量润滑、水溶性切削液和切削油性冷却等常见润滑技术的优缺点,分析了MQL替代传统切削液在切削加工中的利弊,并通过分析MQL在高速加工、铝合金加工及断续加工等方面的应用,探讨了MQL技术的发展趋势及发展过程中凾待解决的问题。     

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.     

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.