已知变差系数的结构强度序贯检验方法

介绍结构可靠性检验的概念和各种强度检验方法的特点，对已知变差系数（Cv法）的均值检验和个值检验方法进行改进，利用可靠性安全系数和各种强度与载荷系数，给出无量纲的判别准则。将变差系数不变的条件引入到序贯检验方法中，推导出新的结构强度检验方法，分析检验变量与均值法的差异，得到两者的近似关系。计算与分析结果表明，均值法效率略高于序贯法，两者分别适用于强度设计裕量较小和较大的情况，扩大了Cv检验方法的使用范围，使检验样本量最小，提高了检验效率；个值法效率最低，不建议采用。     

链条耐磨可靠性指标检验的抽样方法

本文应用最佳检验理论，探讨了链条产品耐磨可靠性指标检验的最佳抽样方法，并给出了各种规格滚子链耐磨可靠性指标检验的抽样方案。     

面向不完全维修的数控机床可靠性评估

为实现不完全维修条件下的数控机床可靠性评估,提出基于对数线性比例强度模型(Log-linear proportional intensity model, LPIM)的多台数控机床可靠性评估方法,建立故障时间的对数线性比例强度函数式。用极大似然估计法和Fisher信息矩阵法给出了模型参数的点估计与区间估计,给出机床可靠性指标的点估计和基于Delta法的区间估计,采用似然比检验方法对时间趋势和修复功效的显著性进行检验。实例分析表明,考虑维修活动影响时,LPIM优于Weibull分布法和非齐次泊松过程模型,能定量反映出维修对机床可靠性的作用,得出的瞬时和累积可靠性特性更符合实际。     

数控车床故障机理分析方法的研究

结合数控车床故障检测的要求对国产某数控车床进行了故障数据采集和分析处理,建立了故障间隔时间的数学模型并采用D检验法进行检验.进行了故障分析,对数控车床进行了评价,剖析了数控车床的故障发生机理,找出了产品的薄弱环节,提出了部件或子系统的可靠性改进建议,为纠正故障指出了明确方向.实践表明该方法为该型数控车床的可靠性提高提供了理论依据.     

一种新的疲劳强度可靠性设计方法——等效应力法

本文根据机械零件疲劳强度理论及可靠性设计理论，提出了一种只利用材料的Ｒ－Ｓ－Ｎ曲线即可进行零部件任意循环特征及任意疲劳寿命时疲劳强度的可靠性设计方法－等效应力法，从而避免了以可靠性设计法计算繁琐、结果误差较大的弊端。     

可靠性试验数表的数值逼近方法研究

本文提出了应用数值逼近方法统计计算可靠性试验常用数表的思想及利用计算机快速、简捷地实现数表功能的方法，并以x^2分布分位数表的实现为例，进行料为详细的论述。以上研究内容可广泛地应用于可靠性统计分析、数据处理、拟合检验、数据库建立等方面。     

数控磨床头架系统可靠性建模与评估

头架系统是数控磨床的关键功能部件,其可靠性高低对磨床的加工质量和效率有重要的影响。根据采集到的故障数据和常用的故障分布类型,应用回归分析法和最大似然估计法对MKS系列数控磨床建立指数分布模型和威布尔分布模型,以获取分布函数及相关参数,用相关系数法和最小距离之和法检验建立模型合理性。根据建立的数学模型计算可靠性指标MTBF,与观测值进行比较,验证所建模型的正确性,为数控磨床可靠性提升提供理论依据。这里所建模型及评估方法已应用于某机床厂的可靠性提升工程中。     

基于有限元法的加氢精制反应器的可靠性分析

用蒙特卡罗法和有限元相结合方法对加氢精制反应器模型进行5000次抽样,并对其可靠性和灵敏性进行分析.结果表明,影响最大的因素是工作压力,这给加氢精制反应器的制造和检验提供了参考.     

基于模糊可靠性的联合收割机脱粒主轴的强度计算

采用模糊可靠性的设计方法，对联合收割机的脱粒主轴进行了强度计算，同时，对比于安全系数设计法和常规可靠性设计。从另一方面说明了模糊可靠性设计的优越性和合理性，是一种比较理想的强度设计方法。     

称重传感器的可靠性设计、控制与管理

可靠性已成为称重传感器的重要质量指标和市场竞争力的主要标志。结合我国称重传感器研制生产中出现的稳定性、可靠性问题，以“产品的可靠性是设计出来的，生产出来的，管理出来的”理念为指导，较详细的论述了称重传感器的可靠性设计，生产过程中的可靠性控制，可靠性管理。介绍了可靠性设计、生产、试验、分析和管理诸环节的关系。分析了影响称重传感器可靠性的系统性和随机性因素，以及最大限度的排除各种不可靠因素的工艺方法，并提出了提高称重传感器固有可靠性的措施。     

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.