基于可靠性的多部件港口设备机会维修模型

为解决多部件港口设备维修不合理的问题,引入设备的机会维修可靠性阈值,以此为基础判断各部件是否需要进行预防性机会维修或更换。以设备总维修成本最小化为目标、设备满足生产需求可用度为条件,建立了设备各部件的机会维修模型。运用MATLAB编程仿真,进行实例分析,求解出港口设备系统中各部件的最优机会维修计划。结果显示,对部件进行机会维修可以有效降低设备的维修成本,并提高其可用度。     

民机系统部件维修间隔优化

在民机维修规划中,针对系统部件维修间隔优化的问题,考虑可靠性影响及经济性因素,确定飞机系统部件最优维修间隔.提出运用改进的三参数威布尔极大似然估计法,求解部件可靠性数据的分布参数,获得维修项目在不同故障影响类型下的可靠寿命方程,并建立了可靠寿命区间约束下的维修费用率优化模型,运用遗传算法进行求解,制定出最优维修间隔期.通过实例分析,对比部件维修技术报告参考值,验证了本方法的可行性,为合理制定维修计划提供了理论依据.     

基于可用度和维修成本的设备维修建模与优化

研究多部件混联机械设备的维修建模与优化问题。以设备许用可用度为约束条件，以维修成本最低为目标，以维修周期为变量，建立设备维修优化模型。利用Monte Carlo仿真求解目标函数，采用基于事件排序的可变步长时钟推进机制，利用投影法统计固定时间区间内的故障次数及故障持续时间，基于最小路集判断设备运行状态，提出了防止部件出现过度故障的故障屏蔽法，利用遗传算法的搜索能力实现目标函数的全局寻优。以一齿链复合传动系统为例，验证模型及解法的有效性。     

装卸料机管嘴组件的可靠性分析

文章阐述了装卸料机的重要组成部件—管嘴组件的功能,并以可靠性为中心的维修分析方法(RCM)对管嘴组件进行分析,从其功能故障、失效模式、设备关键度和维修任务着手,对装卸料机系统相关的运行试验和预防性维修项目重新进行系统性的分析和评价,优化现有预防性维修大纲,提高在役设备可靠性,降低设备故障率,保障装卸料机系统的稳定运行。     

基于设备有效度和可靠度的预防修经济优化模型

基于以可靠性为中心的预防性维修计划对生产的重要性及其制定的复杂性,分析生产设备各单部件最优预防修策略。为了减少维修停机损失,将多个维修作业按照机会维修阈值进行归并。在此基础上分析系统维修费用构成和系统有效度,并以系统总体维修费用最小化、系统有效度最大化为目标,建立多部件成组预防修策略优化模型,提出多部件设备非周期预防修计划的优化方法。模型中除了考虑预防性修理和更换等预防修的主要环节之外,还考虑对于非预期故障所采用的小修环节。用Matlab编程仿真求解出满足设备可靠性要求、且维修成本和有效度得到优化的预防性维修计划。结果表明,相比对多个部件单独进行更换或修理,所提出的方法可以节约维修成本并且提高设备的有效度。     

基于T-S模糊故障树的家用空调可靠性分析

为降低家用空调运行故障率以提高用户体验度和减小家用空调高空维修作业风险,提出应用T-S模糊故障树分析法分析家用空调的可靠性.用T-S模糊门描述空调系统各事件间的联系,用模糊数描述部件的故障程度.根据建立的空调系统T-S模糊故障树模型,计算出顶事件不同状态下的模糊失效可能性,分析顶事件不同状态下各部件的重要度,找出影响整...     

以可靠性为中心的多部件系统预防性维修优化研究

分析了生产设备各单部件最优的预防性维修策略,在此基础上给出了多部件成组预防性维修的经济性优化模型,提出了多部件设备非周期预防性维修计划的优化方法.模型中除了考虑预防性修理和更换等预防性维修的主要环节之外,还考虑了对于非预期故障所采用的小修环节,以及预防性维修造成可靠性下降的情况.为了减少维修停机损失,将多个维修作业按照机会维修阈值进行归并.分析了多部件系统预防维修费用构成,建立了以可靠性为中心的多部件系统预防性维修费用的优化模型.用Matlab编程仿真,求解出了满足设备多部件可靠性要求且维修成本最小的预防性维修计划.仿真结果表明,相比对每个部件单独进行更换或修理,所提出的方法可以节约维修成本.     

一种维修备件储备量决策分析模型

依据可靠性理论和设备维修决策理论 ,假设机械设备的寿命分布和维修时间分布均服从指数分布 ,将设备的部件分可修复部件和不可修复部件两大类 ,对维修备件储备量进行科学决策分析 ,提供在给定使用可靠度和给定工作时间的情况下 ,确定机械设备维修备件储备量的计算模型和方法     

南京捷豹牌双级活塞式空气压缩机维修

本文介绍了双级活塞式空气压缩机的内部结构和各部件功能,描述了典型故障的维修方法。此方法提倡自主维修,可操作性强,成功率高。对延长设备使用时间,降低运行成本有一定的推广价值。     

结构区间可靠性分析的可能度法

在进行结构可靠性分析时,将影响结构功能的不确定性设计变量用区间数描述,建立结构可靠性分析的区间应力－区间强度干涉模型。针对两个区间变量情况的区间应力－区间强度干涉模型,定义了结构安全可能度和失效可能度,形成在设计变量分布形式已知或未知时都适用的结构区间可靠性分析的可能度法,建立了结构区间可靠性分析的可能度准则。分析了结构区间可靠性分析可能度法具有的良好数学性质。在已知设计变量在区间取值范围内都服从均匀分布的前提下,研究了结构安全可能度和概率可靠度的关系,认为结构安全可能度可以对结构安全或可靠的程度做出合理的估计。算例验证了区间可靠性分析可能度法的有效性。     

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.