冷轧铝板表面损伤的探讨

通过对轧后铝板表面的扫描电子显微观察,就冷轧铝板表面损伤进行了探讨。实验发现:轧辊表面微凸体对铝板表面的犁削与粘结作用,以及变形区内润滑油膜对铝板表面形貌的屏蔽作用是冷轧铝板表面损伤的主要原因。     

两端固定铝板结构的模态分析

以一个两端固定的铝板结构模态分析为例，说明了现代结构动力学用试验和理论计算以及实验与分析相关的方法，对结构系统进行模态分析的具体方法，阐述了对铝板结构的有限元计算和模态综合技术的应用，本文介绍的实验、计算和分析方法可靠实用，完全适用于其它机械和结构。     

进口与国产PS版用铝板组织与性能的对比

应用阳极覆膜、稀酸浸蚀、组织观察和拉伸试验等方法,对PS版用国产热轧带坯、普通铸轧带坯和电磁铸轧带坯制备的铝板与日本进口优质铝板的显微组织与性能进行了比较,分析了生产工艺对铝板组织与性能的影响。结果表明:国产热轧和铸轧铝板的显微组织相似,经中间退火铝板的较未经退火的细小均匀;电磁铸轧及较高的硅、铁含量均可细化组织;国产铝板的组织均匀性较进口铝板的有一定差距;热轧铝板中的FeAl2颗粒细小、分布弥散,较普通铸轧铝板中的易腐蚀;电磁铸轧铝板中FeAl2颗粒的密度和尺寸较普通铸轧铝板的小,分布也更加均匀;铝板的抗拉强度和伸长率受中间退火后冷轧变形量的影响。     

受拉铝板在激光辐照下的破坏实验研究

测量了激光照射后的受拉铝板试件的剩余强度，观察了不同激光照射时间下的裂纹扩展情况，并首次利用高温精细网格技术测量出试件上由激光破坏引起的裂纹尖端的裂余变形场，为激光照射金属结构的实时动态变形测量提供了新的手段。     

加劲肋联系焊缝的受力研究

在港日起重机金属结构中,对纯起局部稳定作用的加劲肋联系焊缝,如果选择过大,会导致结构的板面变形波浪度过大,在使用过程中发生压曲破坏;反之,如果过小,在使用过程中会产生加劲肋与主承力板面的联系焊缝开裂,导致结构失稳破坏。本文试图利用变形协调原理和马格尔大挠度理论推导出加劲肋联系焊缝计算公式,并用试验对该公式进行验证。使由联系焊缝引起的变形控制在工艺规范范围内,并保证联系焊缝有足够的联接强度。本文还提供了联系焊缝的推荐形式和推荐值。     

电磁成形铝板时变形高度与成形电压的关系

通过纯铝板的电磁自由成形实验，得出了工件最大变形高度与成形电压呈线性关系的结论，列出了线性方程。通过对变形曲线的分析，提出用二次多项式曲线来近似工件的变形曲线。这样，在变形高度与成形电压的线性方程已知的情况下，成形电压确定，工件的近似变形曲线就可以确定。     

H型电磁测厚涡流传感器的时域仿真研究

针对3种典型激励方式(正弦波、三角波及方波)对H型传感器在金属铝板测厚性能方面产生不同影响的问题,提出了先利用Ansoft Maxwell软件的瞬态磁场求解器对H型传感器进行时域仿真分析,然后用基于数据采集卡的测厚系统进行验证的方法。首先采用了Ansoft Maxwell软件的瞬态磁场求解器对H型传感器和金属铝板的建模,分别求解出在3种不同激励信号及不同铝板的厚度下的传感器的感应差压信号,比较分析了所得到的差压信号;然后采用基于凌华DAQ-2205数据采集卡的测厚系统和H型传感器对不同厚度的金属铝片进行试验验证。实验以及研究结果表明:实验涡流测厚系统获得的数据与仿真计算的结果基本相符,由此表明通过利用Ansoft Maxwell软件的瞬态磁场求解器对H型传感器进行时域仿真分析的方法可以获得H型差动式传感器在金属铝板测厚中的最佳激励信号。     

环焊缝错边的圆柱形容器应力场分析和容限探讨

本文利用薄壳理论,计算了柱形容器环焊缝端面上的位移和转角,由变形协调条件得出端面上的边缘内力,由此求得容器应力场的解析解。通过对120个解析计算结果的多元回归,给出了满足工程精度要求的环焊缝错边引起的应力场近似计算式。文中还对容限等问题作了探讨。     

大型薄壁铝板加工工艺研究及应用

针对大型薄壁铝板类零件外形尺寸大,厚度薄,工件刚性差,加工和起吊易变形,复杂孔系加工制造精度控制难度极大的问题,通过改进装夹、选用合适的切削刀具及切削参数等新工艺流程,将大型薄壁铝板的变形量控制在0.5 mm,孔系精度控制在0.1 mm内,较好地满足了设计要求。     

采用移动式阴极制备大尺寸超亲水/超疏水铝板

基于电化学加工方法和氟化处理技术,采用移动式阴极制备了大尺寸超亲水/超疏水铝板,用扫描电子显微镜和能谱仪分别对该铝板表面的形貌和成分进行了分析,并采用接触角测量仪测量了所得表面的接触角和滚动角。结果表明:采用移动式阴极加工大面积超亲水/超疏水铝板是可行的;电化学加工后的超亲水铝板表面存在二元微纳米粗糙结构,对水的接触角约为0°;该超亲水表面经氟化处理后可转变为超疏水表面,对水的接触角为167°,滚动角小于3°。     

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.