装备维修中备件需求率的预计方法

通过研究装备维修过程中器件的固有可靠性和维修性，着重分析了影咱维修器件需求率的主要因素，利用系统建模和仿真的方法，分别针对耗损类型器件和可修复类型器件建立了相应的需求数学模型，最后给出了维修备件需求率的预计方法。     

维修备件基于AHP的ABC分类模型

针对ABC分类在设备维修备件管理中不足以区分重点备件的缺陷,将层次分析法与ABC分类相结合应用于设备维修备件的分类。将维修备件的易得性、关键性和经济性作为分类准则,通过ABC分类来求解备件对分类准则的权重,然后运用层次分析法计算备件的组合权重,再根据组合权重对备件进行ABC分类。该方法用于设备维修备件的分类可以快速有效地找出重点备件．提高备件管理工作的针对性和有效性。     

批量独立可修件的备件需求预测仿真算法

利用Monte Carlo随机仿真技术，采用事件调度法的仿真策略对可修件的使用与维修过程进行仿真，给出了在给定备件和维修分队数量下批量独立可修件的备件保障概率仿真算法，并用一系列计算实倒证明了算法的可行性和正确性，该算法能有效解决安装在不同装备上，具有不同已工作时间、不同故障间隔时间分布、不同修复时间分布的可修件的备件保障概率计算问题，为备件的科学储备提供7有力的决策依据。     

基于可拓工程方法的维修保障系统效能评估研究

分析了维修保障系统效能的影响因素．应用可拓工程方法建立了维修保障系统效能多指标参数的物元可拓评估模型，以定量的结果对维修保障系统效能进行了评估分级，并与层次分析法和突变评价法的结果进行了比较，结论基本一致．为维修保障系统效能评估问题寻求出一种新的方法，其评估结果可为决策提供定量依据．     

进口全自动材料试验机备件国产化的可行性

针对进口全自动材料试验机部分备件更换周期短,且海外直购时间长的问题,结合日常工作中对试验机的故障维修案例,重点探讨了各型号、各阶段购入的进口全自动材料试验机备件国产化的可行性,找到替代进口备件的合理方案。该工作可为提高实验室设备的管理效率提供保障。     

基于南京地铁可维修件管理流程的研究

随着南京地铁线路的不断拓展,可维修件管理问题日益突出。本文主要研究了南京地铁可维修件管理流程;首先,阐述可维修件流程管理的必要性;其次,介绍可维修件的分类;最后,提出如何进行可维修件流程管理以及可维修件流程管理的优点。     

虚拟维修训练的故障建模与仿真

在维修训练领域,通过研究系统故障产生机理,建立一种基于故障传播有向图的系统故障模型,从工程应用角度阐述了其构建规则,基于该模型设计了虚拟维修训练仿真方法。     

基于战时航空装备备件保障度模型的研究

本文着眼于高技术条件下航空装备备件需求量难以确定的问题,首先构建了战时航空装备备件需求评价指标体系,并运用多层次灰色预测模型预测了战时航空装备备件需求率,最后以此为依据建立了航空装备备件保障度模型。     

船舶备件的管理办法

为了加强船舶备件的集中统一管理,做好备件的储备、供应工作,抓好用、管、修、供四个环节,以保证设备正常的维修和检修计划的顺利进行,备件是设备修理的主要物质基础,及时供应备件,可以缩短修理时间、减少机损失,供应质量优良的备件,可以保证修理质量和修理周期,提高设备的可靠性。因此,备件管理是设备维修资源管理的主要组成部分,船舶设备备件的管理好坏将直接影响到设备运转情况,所以要求备件的管理必须有有效的管理办法,具体方法如下：     

关于高速公路机电维修维护管理的探究

目前,高速公路信息化建设发展迅速,而高速公路机电设备的维修维护管理还存在许多不足之处,主要有设备规格不同、维修成本较高及人员专业素质不高等几方面,为了加强高速公路机电设备的维护与维修管理,本文从多方面提出了不足之处,并根据不足之处,提出了相应的改善措施。     

Modeling Failure Process and Quantifying the Effects of Multiple Types of Preventive Maintenance for a Repairable System

In this paper, we consider a repairable system whose failures follow a non‐homogenous Poisson process with the power law intensity function. The system is subject to corrective and multiple types of preventive maintenance. A corrective maintenance has a minimal effect on the system; however, a preventive maintenance may reduce the system's age. We assume the effects of different preventive maintenance on the system are not identical and derive the likelihood function to estimate the parameters of the failure process as well as the effects of preventive maintenance. Moreover, we derive the conditional reliability and the expected number of failures between two consecutive preventive maintenance types. The proposed methods are applied to a real case study of four trucks used in a mining site in Canada. Copyright © 2016 John Wiley & Sons, Ltd.     

A Modeling Framework for Maintenance Optimization of Electrical Components Based on Fuzzy Logic and Effective Age

In this article, the problem of building a model in support of maintenance optimization when the only available information is that elicited from one expert is tackled. In particular, the degradation process affecting the component is modeled by resorting to the concept of effective age. Information is elicited from one expert by following a systematic literature approach, and the theoretical framework of fuzzy logic is used to deal with his or her qualitative statements. A hybrid approach based on Monte Carlo method and fuzzy logic is then applied to evaluate the performance of a given maintenance policy. Finally, the proposed methodology is applied to a real case study dealing with a medium‐voltage test network. Copyright © 2012 John Wiley & Sons, Ltd.     

Observation and Modeling of Brittle Fracture Initiation in a Micro-Heterogeneous Material

Observations and characterization of brittle fracture initiation in a micro-heterogeneous material (sandstone) are conducted using the standard indirect tensile strength test. Acoustic emissions, optical microscopy and scanning electron microscopy (SEM) are employed for monitoring and characterizing the discrete micro-mechanical events preceding macroscopical fracture. The observations suggest that brittle fracture initiation is the end result of a microscopic damage accumulation process. A simple statistical model of micro damage accumulation leading to brittle fracture in a micro-heterogeneous material is also proposed. The model is calibrated by matching the coefficient of variation of measured ultimate stress with that resulting from the proposed model.     

碱性焊条药皮组分与熔敷金属扩散氢含量的关系

用回归正交试验建立了碱性焊条药皮组分与熔敷金属扩散氢含量之间的关系 ,分析了药皮组分及其交互作用对焊缝熔敷金属扩散氢含量的影响 ,提出了根据药皮配方预报熔敷金属扩散氢的方法。     

喷射沉积坯体特征尺寸的神经网络模型建立与仿真

采用神经网络技术建立了沉积坯特征尺寸模型,该模型描述了喷射成形关键工艺参数对沉积坯尺寸的影响规律,模型输出的相对误差为6.58%,RMS(均方差)为0.372mm.模型的仿真结果给出了沉积坯尺寸的变化规律,其中稳态仿真结果可用于预先确定喷射实验中所采用的合适工艺参数;而动态仿真结果表明,雾化气体压力和沉积器平移速度对沉积坯几何尺寸都有较大影响,其中沉积器平移速度具有调节范围大的优点,成为调节沉积坯几何尺寸较合适的工艺参数.     

Modeling and Analysis of Complex Equipment Maintenance Dynamics

An equipment maintenance system is naturally a complex dynamical system. The effective mamanagement must be based on the knowledge of the system＇s intrinsic dynamics. And the strueture of the maintenance system determines its behavior. This paper analyzes the basic structures and elements of a maintenance system for complex multi-components equipment. The maintenance system is considered as a dynamic system whose behavior is influenced by its structure＇s feedback and interaction, and the system＇s available resources. Building the dynamical model with Simulink, we show some results about the maintenance system＇s nonlinear dynamics, ods. The model can be used for understanding and which operational adjustments of maintenance which are never given by stochastic process methdetermining maintenance system behavior, towards n of maintenance requirements and timely supply of maintenance resources can be made in a more informed way.     

脉冲等离子弧快速成形Inconel 625组织性能研究

研究了脉冲等离子弧快速成形Inconel 625镍基高温合金零件的组织特征及力学性能,重点分析了沉积态组织中相析出规律及分布特点。结果表明,沉积态的组织以胞状树枝晶为主,具有较强生长取向性的外延枝晶组织特征,层与层结合处呈现更细小胞状枝晶特征。由于较快的冷却速率,在整个成形零件包括层与层的结合处并未出现严重的显微偏析现象。通过多种分析手段证实了大量不规则形状的弥散Laves相颗粒分布在枝晶间,MC碳化物(包括NbC,TiC)分布在枝晶间及晶界,以及少量针状相δ(Ni3Nb)的析出。力学性能测试结果表明,显微硬度在整个沉积零件分布较为均匀,在260～285HV0.2范围内,在零件的底部及层层的结合处由于更细小的组织而呈现更高的硬度值。由于析出相的弥散强化作用,零件的抗拉强度最高达到750MPa,同时伸长率可达到50%。     

Experimental Observations and Computational Modeling of Fracturing in an Anisotropic Brittle Crystal (Sapphire)

The commonly used fracture criteria-maximum K_I, zero K_II, maximum hoop-stress, and maximum energy-release rate-predict similar fracture paths in isotropic materials, but not in anisotropic materials. In the general anisotropic case, the fracture path depends on the material-symmetry properties, the nature of the applied loads, and the overall geometry of the specimen. In addition, anisotropy in the material's resistance to fracturing plays a key role in defining crack initiation and its propagation path. Experiments are performed on notched specimens made from sapphire, a microscopically homogeneous and brittle single-crystal solid. The force required for fracture initiation is measured. The experimental measurements/observations are compared with the numerical results of the FEM simulations. A stress-based fracture parameter, is shown to be a good measure of the fracture criterion, where σ and E, respectively, are the tensile stress and Young's modulus in the direction normal to the cleavage plane, with surface energy γ , and R is a characteristic length, e.g., the notch radius. This parameter takes into account the effects of the surface energy of the corresponding cleavage plane, as well as the strength of the atomic bonds in the direction normal to the cleavage plane. More than two-thirds of the notched specimens fractured at the point and along a cleavage plane where A is maximum. The measurements of the applied force made it possible to quantitatively obtain a critical value for parameter A. Finally, experiments show that for the notched sapphire specimens the weakest family of cleavage planes, , are the fracture planes, although a few specimens fractured along non-cleavage planes. This revised version was published online in July 2006 with corrections to the Cover Date.