应力分析设计方法中若干问题的讨论

对应力分析设计法中的一些概念和有争议的问题进行了讨论。在介绍了各种类型应力特点的基础上，强调了应力分解与应力分类的不同，概括了应力分解和分类的正确方法。指出应力分解仅涉及如何将应力分解成均布应力，等效的线性分布应力和非线性应力分量，至于怎样将分解出的应力进行分类，完全是由应力所在位置和产生应力的外因决定的。同时也对峰值应力的分布类型、有无自限性和应力分解及分类中需要注意的问题给出了作者的观点。     

基于XRD的Al2O3纳米薄膜残余应力测试

利用X衍射技术测试了物理气相沉积Al2O3纳米薄膜的残余应力，分析了薄膜和基体间的应力测试原理，讨论了沉积温度、沉积速度和薄膜厚度等技术参数对残余应力的影响。实验结果表明，随着沉积温度升高，Al2O3薄膜残余应力值增大；当沉积速度增加时，Al2O3薄膜的残余应力增大，且从拉应力变为压应力；由于热膨胀系数的不同而产生热拉应力和温度不同产生马氏体相变的残余压应力，残余应力值先是随着晶化温度的升高而下降，然后随之而上升，在400℃进行晶化处理时，残余应力值表现为最小；残余应力随着薄膜厚度的增加而不断增大，当薄膜厚度较小时，薄膜残余应力的变化比较平缓，残余应力值较小，有利于提高薄膜界面结合强度。选择合理的薄膜制备参数，能精确地控制薄膜的残余应力，从而达到提高其结合强度的目的。     

相变温度对焊接残余应力的影响规律及机理分析

通过对焊缝金属相变温度、相变膨胀应变和焊接接头残余应力的测试，分析了相变应力的产生及其对焊接残余应力的影响，相变应力不仅能够降低焊缝金属由于热收缩所引起的残余拉伸应力，而且在一定的条件下还可以产生残余压缩应力，论述了相变温度对焊接残余应力的影响规律以及获得残余压缩应力的相变温度范围，试验证明相变温度在100～300℃范围内，焊缝金属可以获得残余压缩应力，其中在190℃左右时残余压缩应力达到最大。     

板材多点反复成形的残余应力分析*

基于对曲板弹塑性弯曲的理论分析，提出了适于板条反复成形应力分析的近似方法，给出了残余应力的计算公式，并对板条反复纯弯曲变形过程的残余应力进行了分析。结果表明，适当选择反复成形的加载路径，可使残余应力明显降低。     

交变载荷下孔边残余应力变化规律的无损研究

用高灵敏度的云纹干涉法，无损研究了冷挤孔边残余应力在交变载荷下的变化规律。使用１２００线／ｍｍ的闪耀正交光栅，实时测量了冷挤孔边正交方向上因残余应力衰减而引起的应变量，估算出了这些方向上的残余应力的衰减量，并研究了不同挤压量下的残余应力衰减规律。试验研究表明，ＬＹ１２ＣＺ试件的孔边残余应力在交变载荷作用下发生了衰减，孔边残余应力的衰减量受挤压量影响，挤压量越大，孔边的残余应力相对衰减量就越小。     

桡动脉血管归一化应力松弛函数

本文报道了正常国人新鲜尸体桡动脉血管进行应力松弛实验的结果，得出了桡动脉血管在应力松弛状态下应力和时间相关的不同效应，用最小二乘法拟合实验曲线，得出了归一化应力松弛函数，曲线及一些重要结论。     

刀刃半径对不锈钢切削表面残余应力影响的模拟

建立了平面应变有限元模型，采用更新的Lagrange方法模拟了奥氏体不锈钢AISI316L的正交切削过程；研究了刀刃圆弧半径对已加工表面残余应力的影响，发现随着半径的增大，残余拉应力和压应力的数值都增大，压应力层厚度也增大，但是拉应力层厚度不变。将模拟结果与实验结果进行对比，发现二者是吻合的，从而验证了有限元模拟的可用性。     

工程机械结构件焊接应力的消除分析

介绍了工程机械结构件焊接残余应力的产生、应力的危害以及减少残余应力的几种方法，通过对焊接燕尾铲形接头应力和端孔接头应力的有限元分析，论证采用这种方法对减小焊接残余应力，防止结构件疲劳开裂的重要作用。     

微机械薄膜低应力工艺及技术的研究

本文研究了硅表面微机械加工薄膜的形成工艺及技术。通过调整各种薄膜生长、掺杂以及退火的条件，得到了较低的薄膜残余应力（ＬＰＣＶＤ多晶硅膜３０ＭＰａ压应力，ＬＰＣＶＤ富硅氮化硅帮ＰＥＣＶＤ氮化硅膜约１００ＭＰａ张应力，Ａｌ膜在３０ＭＰａ范围内由压应力到张应力变化）。另外，采用了复合膜和纹膜技术，用于大幅度地降低薄膜应力，取得了预计的结果。     

碟形封头与简体连接处边缘应力的研究

本文在对碟形容器的边缘应力进行理论分析的基础上，开展实验并对实验结果与理论值进行对比分析，探讨了薄膜应力计算公式的正确性，验证了碟形容器的应力计算方法，对容器应力的实际测量有指导意义。     

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.