Annual Symposium Reliability and Maintainability, 2004 - RAMS最新文献

Variation mode and effect analysis 变异模式及效应分析

Annual Symposium Reliability and Maintainability, 2004 - RAMS Pub Date : 2004-08-24 DOI: 10.1109/RAMS.2004.1285476

A. Chakhunashvili, P.M. Johansson, B. Bergman

引用次数: 41

Reliability importance of components in a complex system 复杂系统中部件可靠性的重要性

Annual Symposium Reliability and Maintainability, 2004 - RAMS Pub Date : 2004-08-24 DOI: 10.1109/RAMS.2004.1285415

Wendai Wang, Niskayuna James Loman, Niskayuna Pantelis Vassiliou

{"title":"Reliability importance of components in a complex system","authors":"Wendai Wang, Niskayuna James Loman, Niskayuna Pantelis Vassiliou","doi":"10.1109/RAMS.2004.1285415","DOIUrl":"https://doi.org/10.1109/RAMS.2004.1285415","url":null,"abstract":"Reliability importance indices are valuable in establishing direction and prioritization of actions related to an upgrading effort (reliability improvement) in system design, or suggesting the most efficient way to operate and maintain system status. Existing indices are calculated through analytical approaches, and application of these indices to complex repairable systems may be intractable. Complex repairable systems are being increasingly seen, and issues related to analytical system reliability and availability solutions are well known. To overcome this intractability, discrete event simulation, through the use of reliability block diagrams (RBD), is often used to obtain numerical system reliability characteristics. Traditional use of simulation results provides no easy way to compute reliability importance indices. To bridge this gap, several new reliability importance indices are proposed and defined in this paper. These indices can be directly calculated from the simulation results and their limiting values are traditional reliability importance indices. Examples are provided to illustrate the application of the proposed importance indices.","PeriodicalId":270494,"journal":{"name":"Annual Symposium Reliability and Maintainability, 2004 - RAMS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123422428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 139

Accelerated tests to determine the reliability of the cable-encapsulant interface 加速测试，以确定电缆封装剂接口的可靠性

Annual Symposium Reliability and Maintainability, 2004 - RAMS Pub Date : 2004-08-24 DOI: 10.1109/RAMS.2004.1285470

S.D. Bhakta, M. Austin

{"title":"Accelerated tests to determine the reliability of the cable-encapsulant interface","authors":"S.D. Bhakta, M. Austin","doi":"10.1109/RAMS.2004.1285470","DOIUrl":"https://doi.org/10.1109/RAMS.2004.1285470","url":null,"abstract":"Encapsulants are mainly used with the cable in various outdoor products, to act as barriers against the operating environment. In some applications, the encapsulants can also be used to provide strain relief for the cable. The reliability of the cable-encapsulant interface is critical for product functionality as well as its long-term reliability. The reliability of this interface depends on the cable and encapsulant chemistry, their interaction, process conditions and other properties like the glass transition temperature (T/sub g/), hardness, coefficient of thermal expansion (CTE) etc. This reliability is usually determined as part of the final product tests. This is very time-consuming and can lead to appreciable loss of design time, especially when failures are discovered at the end. This study has developed quick screening tests which can optimize the process conditions and reasonably determine the reliability of the cable-encapsulant interface, without testing the entire product. The failure at this interface is mainly due to cracking of the cable. The failure mechanism is influenced by the exothermic reaction, cure temperature, hardness and adhesive properties of the encapsulant. The results of these tests have also been correlated to conventional accelerated product tests like ALT, 85/85 to determine their product applicability. Thereby, these tests could be used as a screening tool for the various cable-potting combinations at the start of the design, thus reducing the design time and achieving the required reliability and optimum process conditions.","PeriodicalId":270494,"journal":{"name":"Annual Symposium Reliability and Maintainability, 2004 - RAMS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114926961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

A simplified risk analysis method of complex systems using the global system model 基于全局系统模型的复杂系统简化风险分析方法

Annual Symposium Reliability and Maintainability, 2004 - RAMS Pub Date : 2004-08-24 DOI: 10.1109/RAMS.2004.1285482

T. Kohda, K. Inoue

{"title":"A simplified risk analysis method of complex systems using the global system model","authors":"T. Kohda, K. Inoue","doi":"10.1109/RAMS.2004.1285482","DOIUrl":"https://doi.org/10.1109/RAMS.2004.1285482","url":null,"abstract":"For the risk analysis and the design of safety actions, accident sequence conditions are necessary. FTA (fault tree analysis) is usually used to obtain system failure conditions. However, a fault tree, which depends on the system analyst's judgment and experience, may omit serious failure conditions. Further, FTA does not consider event sequences explicitly. To solve these problems, this paper proposes a simplified risk analysis method of complex systems using the global system model. The basic idea is that a disturbance path combined with the failure of its effective safety actions causes a system accident. Based on this, the proposed method develops a global system model using bond graphs for physical behavior and information flow for computerized actions or human behaviors, derives potential disturbance paths, obtains system failure condition based on the effectiveness of safety actions, and derives and evaluates accident sequence conditions, and modifies safety actions if necessary. The proposed method can obtain all possible accident sequence conditions directly from the global system model and deal with event sequences and the dependency of safety actions explicitly. As long as the design assumptions and the evaluation of the safety actions are correct, the consistency of accident sequence conditions can be guaranteed. An illustrative example shows the details and merits of the proposed method.","PeriodicalId":270494,"journal":{"name":"Annual Symposium Reliability and Maintainability, 2004 - RAMS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115580353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Criticality evaluation for spare parts initial provisioning 备件初始供应的临界性评估

Annual Symposium Reliability and Maintainability, 2004 - RAMS Pub Date : 2004-08-24 DOI: 10.1109/RAMS.2004.1285498

Sang-Chin Yang, Zhong-wei Du

{"title":"Criticality evaluation for spare parts initial provisioning","authors":"Sang-Chin Yang, Zhong-wei Du","doi":"10.1109/RAMS.2004.1285498","DOIUrl":"https://doi.org/10.1109/RAMS.2004.1285498","url":null,"abstract":"Based on the experience of operations and support, the demands for spare parts are usually uncertain and excess stocking is expensive. The provisioning of spare parts frequently experiences variations over a system's life cycle. The provision of insufficient critical items results in costly system downtime. However, the excess of stock can also be costly. The purpose of this paper is to develop an efficient and effective evaluation method to facilitate the initial provisioning of the critical spare parts that have significant impacts on the operational availability and total life-cycle cost as well. The criticality of spare parts is utilized to estimate an appropriate amount of items for the initial provisioning so that the optimal maintenance plan can be achieved. The repair rates of critical items are analyzed and applied to calculate the turn-around-time of repair items. Criticality is used to determine the importance of each end-item in order to accurately derive the initial spare parts lists. The effects of turn-around-time on spares are discussed and applied to evaluate the spare parts criticality. The failure mode, effects and criticality analysis (FMECA) is modified to incorporate both grey relation number (GRN) and turn-around-time (TAT) with the calculation of risk priority number (RPN) of the spares. A system under development is selected to demonstrate the applicability of the evaluation method. The results indicate that both the criticality of spares and the turn-around-time of repairable items have significant influence on the cost-effectiveness curves of the system. Finally, an efficient procedure for the spare parts initial provisioning is suggested to reduce the total life-cycle cost and improve the effects of maintenance planning.","PeriodicalId":270494,"journal":{"name":"Annual Symposium Reliability and Maintainability, 2004 - RAMS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114567344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

Cost constrained reliability maximization of software systems 成本约束下软件系统可靠性最大化

Annual Symposium Reliability and Maintainability, 2004 - RAMS Pub Date : 2004-08-24 DOI: 10.1109/RAMS.2004.1285447

S.S. Gokhale

{"title":"Cost constrained reliability maximization of software systems","authors":"S.S. Gokhale","doi":"10.1109/RAMS.2004.1285447","DOIUrl":"https://doi.org/10.1109/RAMS.2004.1285447","url":null,"abstract":"Architecture-based techniques have been largely used for the reliability assessment of software systems. However, these techniques also enable the exploration of cost/reliability tradeoffs and evaluation of a set of competing architectural alternatives. This paper presents an optimization framework based on an evolutionary algorithm (EA) which can be used to explore cost/reliability tradeoffs based on software architecture. Evolutionary algorithm was used as an optimization technique because of the discontinuous search space, usually nonlinear but monotonic relation between the cost and reliability of individual modules comprising the software, and complex software architectures giving rise to nonlinear dependencies between individual module reliabilities and the overall application reliability. We illustrate the use of the EA using a case study, where the results of the EA are compared with those obtained from exhaustive enumeration. A comparison of the time taken by the EA to generate an optimal solution with the time taken by exhaustive search to generate an optimal solution indicates that the EA can be used to obtain optimal designs with much greater efficiency than exhaustive search.","PeriodicalId":270494,"journal":{"name":"Annual Symposium Reliability and Maintainability, 2004 - RAMS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117026415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Supporting maintenance decisions with expert and event data 利用专家和事件数据支持维护决策

Annual Symposium Reliability and Maintainability, 2004 - RAMS Pub Date : 2004-08-24 DOI: 10.1109/RAMS.2004.1285511

S. Kunttu, H. Kortelainen

{"title":"Supporting maintenance decisions with expert and event data","authors":"S. Kunttu, H. Kortelainen","doi":"10.1109/RAMS.2004.1285511","DOIUrl":"https://doi.org/10.1109/RAMS.2004.1285511","url":null,"abstract":"A successful maintenance program incorporates planning and follow-up processes, including systematic feedback and data collection systems and routines. The aim of our study is to find methods for predicting the number of failures and the time to the next failure using expert data, which is updated with the collected event data. In this study, three methods for predicting the number of failures were compared. The event and expert data was collected from a Finnish board mill. Tested predicted methods included the moving average, and models for the Poisson process and power law process. With our data set, moving average delivered as good estimates as the more sophisticated ones. One of the four test cases showed especially large variations in the recorded yearly failure rate and none of the testing predicting methods delivered reliable estimates in this case. Because maintenance actions are carried out also during other stoppages, the event data proved to be insufficient for time to failure predictions. The results proved that a continuously improving maintenance program should be based, not only on the event data, but also on all other relevant information. This means than data from different sources need to be combined and the quality of the recorded data must be high.","PeriodicalId":270494,"journal":{"name":"Annual Symposium Reliability and Maintainability, 2004 - RAMS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128269618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Maintenance prioritization for multiple concurrent failures in a satellite-based navigation system 卫星导航系统多个并发故障的维护优先级

Annual Symposium Reliability and Maintainability, 2004 - RAMS Pub Date : 2004-08-24 DOI: 10.1109/RAMS.2004.1285512

C. Pinza, R. Arellano, Meng-Lai Yin

引用次数: 1

Design criteria evaluation using and reliability test improvement based field test data on statistical analysis 基于现场测试数据的统计分析，设计标准评估和可靠性测试改进

Annual Symposium Reliability and Maintainability, 2004 - RAMS Pub Date : 2004-08-24 DOI: 10.1109/RAMS.2004.1285442

Wenzhen Yan, A. T. Herfat

引用次数: 2

Probabilistic performance assessment of a roof top wind, solar photo voltaic hybrid energy system 屋顶风、太阳能、光伏混合能源系统的概率性能评估

Annual Symposium Reliability and Maintainability, 2004 - RAMS Pub Date : 2004-08-24 DOI: 10.1109/RAMS.2004.1285521

J. Reddy, D. Reddy

{"title":"Probabilistic performance assessment of a roof top wind, solar photo voltaic hybrid energy system","authors":"J. Reddy, D. Reddy","doi":"10.1109/RAMS.2004.1285521","DOIUrl":"https://doi.org/10.1109/RAMS.2004.1285521","url":null,"abstract":"The escalation in electrical energy costs associated with fossil and nuclear fuels, and enhanced public awareness of potential environmental impacts of conventional energy systems has created an increased interest in the development and utilization of alternate sources. Photo voltaic and wind energy sources are being increasingly recognized as cost effective generation sources in small isolated power systems. A realistic cost benefit analysis requires evaluation models that can recognize the highly erratic nature of these energy sources while maintaining the chronology and inter dependence of the random variables inherent in them. This paper reports the probabilistic performance assessment of a wind, solar photo voltaic (SPV) hybrid energy system. A 400 watt wind electric generator (WEG), 840 WP (peak watt power) solar photo voltaic power generator, 6/spl times/75 Amp-Hour (Ah) backup storage batteries, charge controller (CC), 1 KVA inverter (INV), etc were designed, integrated and optimized to predict the behavior of generating system based on available local wind / solar and load data at Vasavi College of Engineering, Hyderabad, India. Storage batteries can be designed for various hours of uninterrupted power supply in the event of wind & SPV energy failures. This model is useful for evaluating the probabilistic reliability evaluation of generating systems and gaining a better insight in the component sizes needed before they are built. The loss of supply and effects of the randomness of the wind and solar radiation's were presented. The wind solar photo voltaic hybrid energy system (WSPVHES) is working satisfactorily. The above system is reliable and economical for remote applications.","PeriodicalId":270494,"journal":{"name":"Annual Symposium Reliability and Maintainability, 2004 - RAMS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121709094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 36