基于EAHP-FCE方法的民机修理级别确定模型

针对民机维修工程分析中修理级别分析（level of repair analysis,LORA）的研究,在民机维修保障体制特点的基础上综合考虑经济性和非经济性两个因素,对各类影响民机修理级别的评价因素进行综合分析。应用可拓层次分析法（extension analytic hierarchy process, EAHP）与模糊综合评价法（fuzzy comprehensive evaluation, FCE）建立了一种民机修理级别综合评价模型,并采用灰色关联分析法对比验证了模糊评估结果。在模型求解中,利用区间数取代点的值构建判断矩阵,求解各层次指标权重,采用模糊综合评价法求得模糊关系;将指标权重与模糊评估矩阵进行线性结合以求解复杂的多因子包容方程,归一确定最优方案;通过关联系数分析法对比验证可行性方案与理想方案的关联度。通过实例对提出的模型进行了验证,结果表明方案V₃为最佳方案,即修理级别为基地级,与工程文件中的指导基本一致,说明该模型有效可行。所建立的民机修理级别确定模型完善了修理级别分析理论,能够为航空制造商和航空公司在飞机设计和使用阶段对飞机修理级别确定提供参考。     

剪切载荷作用下复合材料挖补修理层合板试验及有限元分析

为了确定剪切载荷作用下含非穿透损伤复合材料挖补修理层合板的破坏模式和抗剪切能力,进行了复合材料挖补修理层合板的剪切试验,并与未损伤复合材料层合板进行对比。试验结果表明,复合材料挖补修理后的层合板具有较高的强度恢复率,且不影响层合板的后屈曲承载能力。同时,建立了剪切载荷作用下复合材料挖补修理层合板的有限元分析（FEA）模型,复合材料母板和补片采用了三维Hashin准则来判定材料失效,母板层与层之间采用零厚度界面单元以有效模拟剪切载荷作用下复合材料母板上、下子板之间的分层。该模型得到的破坏模式与试验结果基本相符。由于挖补修理的设计与工艺复杂性,理论模拟的破坏载荷与试验结果虽不能完全吻合,但其最大15%左右的差异能够满足修理设计的需要。以上结果说明,该模型对剪切载荷作用下复合材料挖补修理层合板的破坏模式和破坏载荷能够进行工程适用的预测。     

基于KLEE和模糊综合评价的作业者认知能力评估

作业者的认知能力是影响作业绩效的重要因素,目前缺少对作业者认知能力的量化评估方法。为解决该问题,针对作业者认知能力评估具有多因素、模糊性等特点,本文综合运用古林法和模糊综合评价法,首先确定认知因素的重要性权值,在明确评价等级的基础上,构建认知因素的隶属度矩阵,最终建立了一种定性分析和定量分析相结合的个体认知能力评估模型。结合作业特点及要求,该模型可对影响作业绩效的人的认知能力进行准确评估。     

修理温度对复合材料层合板拉伸强度的影响研究

分别对[45/0/0/45]、[45/0/45/0/45]和[45/0/45/0/45/0/45]等3种铺层形式的复合材料层合板的表面划伤损伤进行中温和常温贴补修理,对贴补修理后的层合板拉伸强度进行拉伸测试和有限元模拟,评价中温和常温修理的修理效果。结果表明:中温和常温修理都能满足修理要求,中温的修理效果要好于常温的修理效果。有限元模拟结果表明:有限元计算和实验结果偏差在10%以内,建立的有限元模型可以准确预测层合板修理后的拉伸强度。     

军工企业标准化专业任职资格评价体系初探

通过对军工企业标准化专业任职资格体系的研究探索,给出了军工企业标准化从业人员的任职资格能力评价模型及评价因素,对军工企业标准化从业人员进行分级评价,以全面、客观量化评价标准化从业人员的专业能力,引导标准化人员做好职业通道规划。     

预后验决策分析用于优化混凝土桥梁检修规划

桥梁检修规划是基于桥梁可靠度退化模型、检查修理的技术和费用模型之上的一种决策方法,其目的是确定在什么时间对桥梁进行检查、修理,采用什么样的检查和修理技术最为经济。桥梁修理保证在桥梁设计使用期间内桥梁的可靠度不低于规定的限值,修理决策依据桥梁承载力退化模型和荷载模型;桥梁检查是为了进一步获得桥梁承载力和荷载的信息,从而使得修理决策依据的信息越来越充分。将预后验决策方法应用于桥梁的检修规划,确立了一种桥梁检修的规划方法。     

复合材料织物层合板挖补修理软件实现与试验验证

针对单向拉伸载荷作用下复合材料织物层合板胶接挖补修理结构,改进现有解析模型,建立适用于无附加层、附加1层和附加2层结构的阶梯型挖补修理结构和斜切型挖补修理结构的解析分析模型。给出求解算法,定义准确度用于评价数值计算精度,最终实现开发一套界面友好的复合材料胶接挖补修理设计与分析软件。该软件可以求解单向拉伸载荷作用下,复合材料胶接修理结构内部的剪应力场/剪应变场分布,评价搭接板受载情况,并预测结构失效载荷与失效模式。研究中采用T300/CYCOM-970织物作为母板与补片材料,METLBOND1515-4M作为胶层材料,设计进行了一系列阶梯型及斜切型挖补修理验证试验。试件失效载荷与软件计算结果吻合良好,阶梯型最大相差5.7%,斜切型最大相差14.0%。该软件可以对复合材料织物层合板胶接挖补修理进行高效、准确的初步辅助设计与分析。     

机械加工车间操作工安全能力评价

为了准确评价机械加工车间操作工安全能力,为操作员安全培训和技能培训提供参考依据,在能力定义相关研究的基础上,结合机械加工企业生产实际情况,探讨操作工安全能力的概念和内涵,依此概念和内涵建立安全能力层次结构模型,该模型由目标层、准则层和因素层3个层次构成,包括4个二级指标和14个三级指标.针对AHP无法充分考虑评价人员判断的模糊性,采用模糊一致性判断矩阵确定各层次元素的权重系数,从而构建基于FAHP的机加工车间操作工安全能力综合评价模型.利用该评价模型对某机加工车间4名操作工安全能力进行综合评价,能力等级在Ⅳ和Ⅲ之间,结果与实际基本一致,表明了该方法的有效性和准确性.     

单面贴补修理后层合板的拉伸性能

对含孔损伤复合材料层合板单面贴补后进行拉伸试验研究。测量了层合板的应变分布、修理后层合板中心点的离面位移及拉伸强度等, 考察了补片的厚度、大小等因素对修理效果的影响。结果显示, 增加补片的厚度和直径能够提高母板的承拉能力, 但是增加补片的厚度会导致层合板离面位移增大。对无侧边支持的单面贴补层合板进行计算分析时, 必须考虑偏心载荷引起的弯矩的影响。在此基础上, 采用分层损伤判据建立了三维有限元模型, 对单面贴补层合板的破坏机理和拉伸强度进行了计算和分析。结果表明, 修理后层合板的拉伸破坏是由补片或母板内与胶接面相邻的层间分层引起的; 计算结果与试验结果一致。      

N部件串联可修系统的一个新模型及其可靠性分析

本文研究N部件串联可修系统的一个新模型,该模型在经典n部件串联可修系统中引入了修理工可单重延误休假的概念,并且考虑了修理设备可能发生故障而对整个系统可靠性造成的影响。假定修理工的延误休假时间、部件的寿命和修理设备的寿命均服从指数分布,部件的修理时间、修理设备的更换时间和修理工的休假时间均服从一般连续型分布,通过使用补充变量法和广义马尔可夫过程方法得到了系统和修理设备的一些重要可靠性指标。     

Adaptive response: modelling and experimental studies

Adaptive response (AR) is a term that has been generally accepted to describe the ability of a low 'priming' radiation dose to decrease the cell response to a subsequent higher 'challenging' dose. The main proposed mechanisms to explain AR are: increased efficiency of DNA repair and induction of antioxidant enzymes. A model that considers a modulation of the efficiency of DNA repair activity and of the level of antioxidant enzymes, starting from the framework of a lethal-potentially lethal (LPL) model is proposed. The LPL model has been extended with the inclusion of the dynamic variables representing the efficiency of repair, the levels of radiation induced radicals and of antioxidant enzymes. The model used here is able to describe the protective effect of a priming dose. Moreover, in agreement with the data in the literature, the simulations show that the AR happens in given priming dose and priming dose-rate ranges only, and requires at least 4 h to develop. In order to get more insights into the role of cell-cell communication as factors affecting the AR, experimental studies were planned using sparse or confluent AG1522 cell monolayer. The results obtained after gamma irradiation suggest that cell density is a crucial factor for observing an AR.     

Reliability modeling of multi‐state degraded repairable systems and its applications to automotive systems

In this paper, we presented a continuous‐time Markov process‐based model for evaluating time‐dependent reliability indices of multi‐state degraded systems, particularly for some automotive subsystems and components subject to minimal repairs and negative repair effects. The minimal repair policy, which restores the system back to an “as bad as old” functioning state just before failure, is widely used for automotive systems repair because of its low cost of maintenance. The current study distinguishes with others that the negative repair effects, such as unpredictable human error during repair work and negative effects caused by propagated failures, are considered in the model. The negative repair effects may transfer the system to a degraded operational state that is worse than before due to an imperfect repair. Additionally, a special condition that a system under repair may be directly transferred to a complete failure state is also considered. Using the continuous‐time Markov process approach, we obtained the general solutions to the time‐dependent probabilities of each system state. Moreover, we also provided the expressions for several reliability measures include availability, unavailability, reliability, mean life time, and mean time to first failure. An illustrative numerical example of reliability assessment of an electric car battery system is provided. Finally, we use the proposed multi‐state system model to model a vehicle sub‐frame fatigue degradation process. The proposed model can be applied for many practical systems, especially for the systems that are designed with finite service life.     

Modeling the fatigue failure processes in evaluating the reliability of machines and their components

An examination is made of the method of evaluating the reliability of a restored object in failures of elements due to fatigue. The evaluation method is based on simulating the fatigue failure process taking into account its two-stage form, the repair cycle of the object, and crack diagnostics. It is proposed to simulate the working life to the appearance of a fatigue crack by the corrected Serensen-Kogaev linear model of damage cumulation, and simulate the life on the basis of models, constructed using a special multifactor of experiment, which reflect the effect of significant service factors on the crack growth rate. An algorithm of modeling two types of failures of a restored object using the method of statistical testing is proposed. The reliability of a freight-car is evaluated on the basis of failures of a coupler yoke of the automatic coupling device.Translated from Problemy Prochnosti, No. 3, pp. 28–34, March, 1990.     

Optimal load distribution in series-parallel systems

This paper presents an algorithm for determining an optimal loading of elements in series-parallel systems. The optimal loading is aimed at achieving the greatest possible expected system performance subject to repair resource constraint. The model takes into account the dependence of elements’ failure rates on their load. The optimization algorithm uses a universal generating function technique for evaluating the expected system performance, and a genetic algorithm for determining the optimal load distribution. An illustrative example of load distribution optimization is presented.     

Factors affecting opportunity of worksharing as a dynamic line balancing mechanism

We consider the problem of optimal worksharing between two adjacent workers each of whom processes a fixed task in addition to their shared task(s). We use a Markov Decision Process (MDP) model to compute optimal policies and provide a benchmark for evaluating threshold policy heuristics. Our approach differs from previous studies of dynamic line balancing in that we focus on system architecture factors that affect the performance improvement opportunity possible through worksharing relative to a traditional static worker allocations, as well as practical heuristics for worksharing. We find that three such factors are significant whether we use an optimal or a heuristic control policy: ability to preempt the shared task, granularity of the shared task and overall variability of the task times. Understanding the role of these factors in a given production environment provides a means for determining where and how worksharing can have significant logistical benefits.     

基于动态正常模型和免疫计算的软件故障高精度处理

针对软件故障的检测、消除和修复的问题,用动态正常模型和免疫计算的方法进行了软件故障高精度处理的研究.动态的正常模型用来提高软件故障检测的精度,免疫计算用来提高软件系统对软件故障的免疫力和修复能力.用正常软件系统中所有组件的时空属性唯一确定了该系统的正常状态,设计了软件故障检测、消除与修复的免疫算法,包括自体/软件故障的检测算法、已知软件故障的识别算法、未知软件故障的识别算法、软件故障的消除算法和受损系统的修复算法.在时间属性正确的条件下,软件系统的正常模型大大提高了对软件故障的检测率(理论上可达到100%),降低了误检率.正常模型和免疫计算有助于从精度和智能两方面同时解决软件系统的安全性问题,为未来软件的设计与工程化提供有用的创新思路.     

动态联盟伙伴选择的组合评价研究

联盟伙伴的评价是动态联盟伙伴选择的重要一环。分析了动态联盟伙伴选择过程中定性和定量因素,针对盟主对联盟伙伴采用单一评价方法的不足,提出了要用多种方法对潜在联盟伙伴进行评价。给出了各种方法评价结果的二致性检验模型和组合评价模型。在实例中,对三种成熟的评价方法的结果进行组合评价,使得最终的评价结果更为科学、合理。     

Analysis of two-machine lines with finite buffer,operation-dependent and time-dependent failure modes

An analytical model for evaluating the throughput of two-machine lines, characterised by intermediate buffer with finite capacity, deterministic processing times and multiple failure modes for each machine is presented in this paper. Both operation-dependent failure and time-dependent failure are captured in a unique model as extension of the existing literature that was dealing with either one of them. Each machine has two failure modes, one is operation-dependent and the other is time-dependent. Time to failure and time to repair are assumed to be geometrically distributed. The presented method calculates the steady-state probabilities of the manufacturing system with a computational effort that depends only on the number of failure modes and not on the buffer capacity. A performance comparison of the proposed model with existing techniques is also reported, the aim is to show the error introduced by an analytical model that considers the operation-dependent failure mode as approximation of the time-dependent one.     

Research on Evaluation and Management of Networked Manufacturing Resources Based on WUXIASP

1Introduction Themanufacturingresource(MR)isafloorboardofallphysicselementsinproductionactivityabout allproductlifetime.Inatraditionalmanufacturingmode,thecorrespondingdemandsofitarecom monlyputforwardaccordingtodifferentphasesinproductionprocessesandasinglecomputerappli cationsystem;thusitisincapableofmeetingtheneedsofthedecentralizationandnetworkedmanu facturing.Thenetworkedmanufacturingsystem(NMS)isadecentralizingandisomerousmanufac turingentity.ThemanufacturingresourcesinNMS,especially…