Pub Date : 1900-01-01DOI: 10.1109/RAM.2017.7889726
S. Sridharan, S. Mangalam
The harmful consequences of carbon monoxide (CO) within indoor environments is globally regarded as a safety issue. In the context of fuel-burning appliances, routine maintenance is vital to ensuring the safe equipment performance, and avoiding exposure to unacceptable levels of CO formed due to improper fuel combustion. However, the enforcement of maintenance requirements in certain locations, such as residences, could be hindered by factors including a lack of jurisdiction to enforce, or restrictions imposed by regulations, thus adding to the complexities faced by regulators in managing this risk to the public. Additionally, maintenance processes can be intensive and challenging to follow due to such considerations as cost, as well as a lack of awareness of obligations. This paper focuses on the complexities around managing the risk of failure in a regulatory context, associated with fuel-burning appliances across various locations given the aforementioned complexities. A special emphasis will be given towards the risk of CO release in residences. The paper will use actual evidence, innovative risk measurements to contextualise the unique challenges with the management of residential CO risk.
{"title":"Carbon monoxide risks and implications on maintenance-intensive fuel-burning appliances — A regulatory perspective","authors":"S. Sridharan, S. Mangalam","doi":"10.1109/RAM.2017.7889726","DOIUrl":"https://doi.org/10.1109/RAM.2017.7889726","url":null,"abstract":"The harmful consequences of carbon monoxide (CO) within indoor environments is globally regarded as a safety issue. In the context of fuel-burning appliances, routine maintenance is vital to ensuring the safe equipment performance, and avoiding exposure to unacceptable levels of CO formed due to improper fuel combustion. However, the enforcement of maintenance requirements in certain locations, such as residences, could be hindered by factors including a lack of jurisdiction to enforce, or restrictions imposed by regulations, thus adding to the complexities faced by regulators in managing this risk to the public. Additionally, maintenance processes can be intensive and challenging to follow due to such considerations as cost, as well as a lack of awareness of obligations. This paper focuses on the complexities around managing the risk of failure in a regulatory context, associated with fuel-burning appliances across various locations given the aforementioned complexities. A special emphasis will be given towards the risk of CO release in residences. The paper will use actual evidence, innovative risk measurements to contextualise the unique challenges with the management of residential CO risk.","PeriodicalId":138871,"journal":{"name":"2017 Annual Reliability and Maintainability Symposium (RAMS)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127494482","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}
Pub Date : 1900-01-01DOI: 10.1109/RAM.2017.7889669
Yuan Li, Shaoping Wang, Jian Shi, M. Tomovic
The paper proposes a performance degradation analysis model based on dynamic erosion wear for novel Linear Electro-Hydraulic Actuator (LEHA). The Computational Fluid Dynamics (CFD) method, combining with turbulent theory and micro erosion principle, is used to establish an erosien model of rectification mechanism. The erosion rate of different port opening size under time-varying flow field was obtained. By piecewise linearization method, we updated the concentration of contaminated particles within LEHA and gained the structure erosion degradation process at the different stages of degradation. The innovation of our model is using dynamic contaminated particles concentration, while static particles concentration in erosion analysis for Electrohydraulic Servo Valve (EHSV), throttle valve, spool valve, needle valve published in the previous literatures. The approach can be used to evaluate the service life of LEHA, further to guide the design of LEHA's rectification valve structure. Our efforts can make LEHA more resistant to erosion.
{"title":"Dynamic contaminated particles concentration-based degradation model of linear electro-hydrostatic actuator","authors":"Yuan Li, Shaoping Wang, Jian Shi, M. Tomovic","doi":"10.1109/RAM.2017.7889669","DOIUrl":"https://doi.org/10.1109/RAM.2017.7889669","url":null,"abstract":"The paper proposes a performance degradation analysis model based on dynamic erosion wear for novel Linear Electro-Hydraulic Actuator (LEHA). The Computational Fluid Dynamics (CFD) method, combining with turbulent theory and micro erosion principle, is used to establish an erosien model of rectification mechanism. The erosion rate of different port opening size under time-varying flow field was obtained. By piecewise linearization method, we updated the concentration of contaminated particles within LEHA and gained the structure erosion degradation process at the different stages of degradation. The innovation of our model is using dynamic contaminated particles concentration, while static particles concentration in erosion analysis for Electrohydraulic Servo Valve (EHSV), throttle valve, spool valve, needle valve published in the previous literatures. The approach can be used to evaluate the service life of LEHA, further to guide the design of LEHA's rectification valve structure. Our efforts can make LEHA more resistant to erosion.","PeriodicalId":138871,"journal":{"name":"2017 Annual Reliability and Maintainability Symposium (RAMS)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116852576","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}
Pub Date : 1900-01-01DOI: 10.1109/RAM.2017.7889677
Paul T. Dube, Debra Greenhalgh Lubas
Delivering systems which meet correctly specified requirements, are appropriately designed, verified and validated is the primary objective of The Naval Sea Systems Command (NAVSEA). Continuous technology upgrades of systems allow the Navy to deliver increased capabilities to its fleet without a need to be reliable for the life of the ships. When equipment upgrades are preplanned, a balance must be struck between the Navy's need to ensure that its ships operate without mission critical failures, the cost and the ability to repair the equipment when failures ultimately occur. Vice Admiral Thomas J. Moore, the new commander of NAVSEA has made on-time delivery of ships and submarines from maintenance availabilities his No. 1 priority [1]. “We have consistently underestimated at the beginning of the year what the requirement is for maintenance,” Moore said, also noting that ships are often late “because we had more growth in the work package [than planned]”. Reliability and Maintainability Engineering (R&ME) requirements will drive industry to deliver systems which ensure that a ship can continuously operate during its deployment and within the planned lifecycle constraints. Improved Department of Defense (DoD) policy and standards in R&ME will save the Navy millions of dollars in repair parts procurements and maintenance costs as the Navy improves its design and development processes.
交付符合正确规定要求、经过适当设计、验证和验证的系统是海军海上系统司令部(NAVSEA)的主要目标。系统的持续技术升级使海军能够为其舰队提供更高的能力，而不需要在舰船的使用寿命内保持可靠。当预先计划设备升级时，必须在海军确保其舰艇在没有关键任务故障的情况下运行的需求，成本和最终发生故障时修复设备的能力之间取得平衡。海军中将托马斯·j·摩尔(Thomas J. Moore)是新上任的海军海洋司令部司令，他将按时交付舰船和潜艇作为其首要任务[1]。摩尔说:“我们在年初一直低估了维护的需求。”他还指出，船只经常迟到，“因为我们的工作包(比计划)增长得更多。”可靠性和可维护性工程(R&ME)需求将推动行业交付确保船舶在部署期间和计划生命周期限制内持续运行的系统。随着海军改进其设计和开发过程，改进的国防部(DoD) R&ME政策和标准将为海军节省数百万美元的维修零件采购和维护成本。
{"title":"Evolutionary reliability & maintainability strategy improves Navy ships","authors":"Paul T. Dube, Debra Greenhalgh Lubas","doi":"10.1109/RAM.2017.7889677","DOIUrl":"https://doi.org/10.1109/RAM.2017.7889677","url":null,"abstract":"Delivering systems which meet correctly specified requirements, are appropriately designed, verified and validated is the primary objective of The Naval Sea Systems Command (NAVSEA). Continuous technology upgrades of systems allow the Navy to deliver increased capabilities to its fleet without a need to be reliable for the life of the ships. When equipment upgrades are preplanned, a balance must be struck between the Navy's need to ensure that its ships operate without mission critical failures, the cost and the ability to repair the equipment when failures ultimately occur. Vice Admiral Thomas J. Moore, the new commander of NAVSEA has made on-time delivery of ships and submarines from maintenance availabilities his No. 1 priority [1]. “We have consistently underestimated at the beginning of the year what the requirement is for maintenance,” Moore said, also noting that ships are often late “because we had more growth in the work package [than planned]”. Reliability and Maintainability Engineering (R&ME) requirements will drive industry to deliver systems which ensure that a ship can continuously operate during its deployment and within the planned lifecycle constraints. Improved Department of Defense (DoD) policy and standards in R&ME will save the Navy millions of dollars in repair parts procurements and maintenance costs as the Navy improves its design and development processes.","PeriodicalId":138871,"journal":{"name":"2017 Annual Reliability and Maintainability Symposium (RAMS)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116600967","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}
Pub Date : 1900-01-01DOI: 10.1109/RAM.2017.7889784
Jingxiu Yao, Yumei Wu, B. Liu
This paper proposes a new optimized method for fault propagation analysis (FPA) of mechatronic systems. In order to analyze the fault propagation to locate the most vulnerable point, the relevant components of this type of system, such as the software, are abstracted into corresponding models. Firstly, we use a novel graphical representation of a module-signal diagram (MSD) transformed to a signal fault propagation tree (SFPT) and a module fault propagation tree (MFPT). Then fault propagation characteristic parameters are defined to calculate the index of vulnerability for the modules. Meanwhile, a method is presented to find out the most vulnerable path. Finally, a case study of a four-rotor unmanned helicopter is provided to demonstrate and validate the proposed method. By injecting fault to attitude adjustment software modules, we can obtain the fault propagation probability of all modules and the data transfer probability from a module to signals. Then the corresponding SFPT and MFPT can be built from the MSD of the attitude adjustment software system. The final result is the most vulnerable module and path of the example system after performing the proposed method of fault propagation analysis. The result can be used for predicting to locate the fault of mechatronic software systems.
{"title":"An optimized method for fault propagation analysis of mechatronic systems","authors":"Jingxiu Yao, Yumei Wu, B. Liu","doi":"10.1109/RAM.2017.7889784","DOIUrl":"https://doi.org/10.1109/RAM.2017.7889784","url":null,"abstract":"This paper proposes a new optimized method for fault propagation analysis (FPA) of mechatronic systems. In order to analyze the fault propagation to locate the most vulnerable point, the relevant components of this type of system, such as the software, are abstracted into corresponding models. Firstly, we use a novel graphical representation of a module-signal diagram (MSD) transformed to a signal fault propagation tree (SFPT) and a module fault propagation tree (MFPT). Then fault propagation characteristic parameters are defined to calculate the index of vulnerability for the modules. Meanwhile, a method is presented to find out the most vulnerable path. Finally, a case study of a four-rotor unmanned helicopter is provided to demonstrate and validate the proposed method. By injecting fault to attitude adjustment software modules, we can obtain the fault propagation probability of all modules and the data transfer probability from a module to signals. Then the corresponding SFPT and MFPT can be built from the MSD of the attitude adjustment software system. The final result is the most vulnerable module and path of the example system after performing the proposed method of fault propagation analysis. The result can be used for predicting to locate the fault of mechatronic software systems.","PeriodicalId":138871,"journal":{"name":"2017 Annual Reliability and Maintainability Symposium (RAMS)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115319894","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}
Pub Date : 1900-01-01DOI: 10.1109/RAM.2017.7889665
Fengbin Sun, Jiliang Zhang
Authors of this paper summarize and discuss various scenarios in real world reliability engineering practice where fractional failures and fractional survivors can be encountered. Examples are given to illustrate their manifestation, failure classification and fractional failure determination, data entry format, life distribution parameter estimation, reliability quantification, and field risk prediction. It is the authors' belief that fractional failure will become a norm, instead of an exception, due to various reasons. They include, but are limited to: the nature of failure initiation, development, and manifestation, effectiveness of corrective actions, failure-physics based identification of the sub-healthy condition using parametric degradation analysis techniques, failure analysis resource and capability limitation, etc. It is hoped that this paper will be beneficial to a wide audience including reliability engineers, theorists, and management.
{"title":"Dealing with fractional failures and survivors in data analysis of reliability engineering","authors":"Fengbin Sun, Jiliang Zhang","doi":"10.1109/RAM.2017.7889665","DOIUrl":"https://doi.org/10.1109/RAM.2017.7889665","url":null,"abstract":"Authors of this paper summarize and discuss various scenarios in real world reliability engineering practice where fractional failures and fractional survivors can be encountered. Examples are given to illustrate their manifestation, failure classification and fractional failure determination, data entry format, life distribution parameter estimation, reliability quantification, and field risk prediction. It is the authors' belief that fractional failure will become a norm, instead of an exception, due to various reasons. They include, but are limited to: the nature of failure initiation, development, and manifestation, effectiveness of corrective actions, failure-physics based identification of the sub-healthy condition using parametric degradation analysis techniques, failure analysis resource and capability limitation, etc. It is hoped that this paper will be beneficial to a wide audience including reliability engineers, theorists, and management.","PeriodicalId":138871,"journal":{"name":"2017 Annual Reliability and Maintainability Symposium (RAMS)","volume":"433 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115625239","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}
Pub Date : 1900-01-01DOI: 10.1109/RAM.2017.7889712
Saikath Bhattacharya, V. Nagaraju, L. Fiondella, Eric Spero, A. Ghoshal
Tradespace Exploration (TSE) is a Department of Defense (DOD) Engineered Resilient Systems (ERS) thrust, with overarching goals to develop processes and products capable of performing in a wide range of adverse conditions commonly encountered by military systems. TSE technologies are modernizing system engineering, facilitating stakeholder engagement through distributed collaborative environments for design and analysis of alternatives. However, the majority of TSE research emphasizes tradeoffs between functional requirements, especially those related to performance, not nonfunctional requirements such as reliability, availability, and maintainability, which impact operation and support costs (O&S). This paper presents a model to explicitly consider the impact of reliability improvement on availability and cost with special attention to fleet size and average procurement unit cost (APUC). Examples illustrate how reliability improvement could significantly increase availability as well as reduce lifecycle and average procurement unit cost.
{"title":"Reliability improvement to minimize average procurement unit cost of a rotorcraft fleet","authors":"Saikath Bhattacharya, V. Nagaraju, L. Fiondella, Eric Spero, A. Ghoshal","doi":"10.1109/RAM.2017.7889712","DOIUrl":"https://doi.org/10.1109/RAM.2017.7889712","url":null,"abstract":"Tradespace Exploration (TSE) is a Department of Defense (DOD) Engineered Resilient Systems (ERS) thrust, with overarching goals to develop processes and products capable of performing in a wide range of adverse conditions commonly encountered by military systems. TSE technologies are modernizing system engineering, facilitating stakeholder engagement through distributed collaborative environments for design and analysis of alternatives. However, the majority of TSE research emphasizes tradeoffs between functional requirements, especially those related to performance, not nonfunctional requirements such as reliability, availability, and maintainability, which impact operation and support costs (O&S). This paper presents a model to explicitly consider the impact of reliability improvement on availability and cost with special attention to fleet size and average procurement unit cost (APUC). Examples illustrate how reliability improvement could significantly increase availability as well as reduce lifecycle and average procurement unit cost.","PeriodicalId":138871,"journal":{"name":"2017 Annual Reliability and Maintainability Symposium (RAMS)","volume":"270 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123446810","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}
Pub Date : 1900-01-01DOI: 10.1109/RAM.2017.7889734
Miklos Szidarovszky, Huairui Guo, F. Szidarovszky, M. Hijawi
Warranty prediction is a very important task in reliability engineering. It needs to estimate the expected number of failures in any given time period during the length of the warranty contract. Several commercial software packages have been already implemented and used in the industry, including Minitab and Weibull++. The time to failure is usually selected to be a Weibull distribution and no technology improvement in the manufacturing process or in the product design is assumed. This paper introduces a new mathematical model which provides the requested predictions under much more general conditions. It is very common that the design and the manufacturing process of an item will change to fix issues discovered in the field. These changes will result in the change of the failure behavior which is often modeled by a time to failure distribution such as Weibull. In our model we consider a manufacturing plant producing identical items in given numbers during each time period. They are subject to possible failures in any later time period after they are produced and the replacements also can fail later as newly produced items. It is assumed that at a given later time, the technology changes so the time to failure distribution also changes, and all items which are replaced or produced from this time period will follow the new time to failure distribution. In order to plan appropriate inventory strategy it is necessary to predict the expected total number of failures in every time period during the considered warranty time interval. In computing the total number of failures the cumulative effect of the failures of new items as well as those of their possible replacements have to be considered and taken into account. A mathematical model is first introduced, where, for the sake of simplicity, it is assumed that after introducing the new technology the produced or replaced items will no longer fail. The general case can be, however, considered and solved in a similar way. In addition to an analytic solution methodology a simulation study is presented. The Weibull distribution is used in the numerical example, however, it can be replaced with any other distribution type. It is demonstrated that the usual prediction method can be successfully extended into cases when the improvement of the production technology changes the distribution of the time to failure, and therefore the probabilistic properties of all items produced or replaced after this change are also changed. The expectation of the cumulative number of failures in each time period provides important help in finding the most appropriate inventory strategies leading to significant savings in inventory cost as well as in the cost of delayed services.
{"title":"Warranty prediction for parts with design changes","authors":"Miklos Szidarovszky, Huairui Guo, F. Szidarovszky, M. Hijawi","doi":"10.1109/RAM.2017.7889734","DOIUrl":"https://doi.org/10.1109/RAM.2017.7889734","url":null,"abstract":"Warranty prediction is a very important task in reliability engineering. It needs to estimate the expected number of failures in any given time period during the length of the warranty contract. Several commercial software packages have been already implemented and used in the industry, including Minitab and Weibull++. The time to failure is usually selected to be a Weibull distribution and no technology improvement in the manufacturing process or in the product design is assumed. This paper introduces a new mathematical model which provides the requested predictions under much more general conditions. It is very common that the design and the manufacturing process of an item will change to fix issues discovered in the field. These changes will result in the change of the failure behavior which is often modeled by a time to failure distribution such as Weibull. In our model we consider a manufacturing plant producing identical items in given numbers during each time period. They are subject to possible failures in any later time period after they are produced and the replacements also can fail later as newly produced items. It is assumed that at a given later time, the technology changes so the time to failure distribution also changes, and all items which are replaced or produced from this time period will follow the new time to failure distribution. In order to plan appropriate inventory strategy it is necessary to predict the expected total number of failures in every time period during the considered warranty time interval. In computing the total number of failures the cumulative effect of the failures of new items as well as those of their possible replacements have to be considered and taken into account. A mathematical model is first introduced, where, for the sake of simplicity, it is assumed that after introducing the new technology the produced or replaced items will no longer fail. The general case can be, however, considered and solved in a similar way. In addition to an analytic solution methodology a simulation study is presented. The Weibull distribution is used in the numerical example, however, it can be replaced with any other distribution type. It is demonstrated that the usual prediction method can be successfully extended into cases when the improvement of the production technology changes the distribution of the time to failure, and therefore the probabilistic properties of all items produced or replaced after this change are also changed. The expectation of the cumulative number of failures in each time period provides important help in finding the most appropriate inventory strategies leading to significant savings in inventory cost as well as in the cost of delayed services.","PeriodicalId":138871,"journal":{"name":"2017 Annual Reliability and Maintainability Symposium (RAMS)","volume":"2008 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129636182","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}
Pub Date : 1900-01-01DOI: 10.1109/RAM.2017.7889791
Darryl W. Kellner, Steve Rogers, Antonio Scappaticci, E. Schwartz
This paper investigates how reliability professionals can use limited failure test data in determining an estimated failure rate on a developmental mechanical system or component. To assess whether a mechanical system or component meets a program's reliability requirement, a Weibull model is the most commonly used distribution to employ for determining a failure rate and the probability of failure during a system or component's required life. Using limited failure test data to determine a predicted failure rate introduces several challenges in application, but can be a cost-effective and expedient approach to use during the early prototyping and technology demonstration phases when test data is available. This approach was successfully implemented by the authors to determine a component-level failure rate, which was then used to perform additional safety analysis. The early insights gained from this reliability prediction approach and additional focused analysis resulted in design improvements in the fielded configuration and provided and early indication that the reliability requirement could be met.
{"title":"Reliability prediction using limited test data","authors":"Darryl W. Kellner, Steve Rogers, Antonio Scappaticci, E. Schwartz","doi":"10.1109/RAM.2017.7889791","DOIUrl":"https://doi.org/10.1109/RAM.2017.7889791","url":null,"abstract":"This paper investigates how reliability professionals can use limited failure test data in determining an estimated failure rate on a developmental mechanical system or component. To assess whether a mechanical system or component meets a program's reliability requirement, a Weibull model is the most commonly used distribution to employ for determining a failure rate and the probability of failure during a system or component's required life. Using limited failure test data to determine a predicted failure rate introduces several challenges in application, but can be a cost-effective and expedient approach to use during the early prototyping and technology demonstration phases when test data is available. This approach was successfully implemented by the authors to determine a component-level failure rate, which was then used to perform additional safety analysis. The early insights gained from this reliability prediction approach and additional focused analysis resulted in design improvements in the fielded configuration and provided and early indication that the reliability requirement could be met.","PeriodicalId":138871,"journal":{"name":"2017 Annual Reliability and Maintainability Symposium (RAMS)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128892600","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}
Pub Date : 1900-01-01DOI: 10.1109/RAM.2017.7889695
L. H. Crow
The planned reliability growth curve gives the interim milestone reliability targets in which the system is judged as the reliability growth program progresses across single or multiple test phases. At the end of each test phase the system reliability is assessed and compared to the corresponding value on the planned reliability growth curve. If the assessed reliability is on or above the milestone value, the reliability program continues. If the assessed reliability is below the milestone value changes in the reliability program may be necessary. It is therefore important that the planned reliability growth curve be realistic and based on input parameters and assumptions that adequately reflect the configuration and characteristics of the system. This paper addresses the development of a reliability growth planning model for discrete systems that includes a growth rate parameter which is a user input. The motivation for this paper is that the current DoD reliability growth planning model for discrete systems, the Discrete PM2 model, Refs.10, 11, does not have a growth rate or a comparable quality. The consequence of this is that there is no parameter in the PM2 model in which the user can input, or calculate, that gives the rate of growth and provides a basis for determining the test resources that are necessary and realistic in order to attain the reliability goal or requirement In this paper the Extended Discrete planning model is presented which has the same fundamental inputs as the Extended Continuous Reliability Growth planning, including a growth parameter. This discrete planning models allows for the development of a planned curve that utilizes historical growth rate data and provides a parameter that can aid in the practical allocated of test resources. The Extended Discrete planning model presented in this paper has a number of engineering and management input parameters that together with the growth parameter provide a broader planning capability than exists in current models.
{"title":"The extended discrete reliability growth planning model","authors":"L. H. Crow","doi":"10.1109/RAM.2017.7889695","DOIUrl":"https://doi.org/10.1109/RAM.2017.7889695","url":null,"abstract":"The planned reliability growth curve gives the interim milestone reliability targets in which the system is judged as the reliability growth program progresses across single or multiple test phases. At the end of each test phase the system reliability is assessed and compared to the corresponding value on the planned reliability growth curve. If the assessed reliability is on or above the milestone value, the reliability program continues. If the assessed reliability is below the milestone value changes in the reliability program may be necessary. It is therefore important that the planned reliability growth curve be realistic and based on input parameters and assumptions that adequately reflect the configuration and characteristics of the system. This paper addresses the development of a reliability growth planning model for discrete systems that includes a growth rate parameter which is a user input. The motivation for this paper is that the current DoD reliability growth planning model for discrete systems, the Discrete PM2 model, Refs.10, 11, does not have a growth rate or a comparable quality. The consequence of this is that there is no parameter in the PM2 model in which the user can input, or calculate, that gives the rate of growth and provides a basis for determining the test resources that are necessary and realistic in order to attain the reliability goal or requirement In this paper the Extended Discrete planning model is presented which has the same fundamental inputs as the Extended Continuous Reliability Growth planning, including a growth parameter. This discrete planning models allows for the development of a planned curve that utilizes historical growth rate data and provides a parameter that can aid in the practical allocated of test resources. The Extended Discrete planning model presented in this paper has a number of engineering and management input parameters that together with the growth parameter provide a broader planning capability than exists in current models.","PeriodicalId":138871,"journal":{"name":"2017 Annual Reliability and Maintainability Symposium (RAMS)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125293712","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}
Pub Date : 1900-01-01DOI: 10.1109/RAM.2017.7889745
G. Morris
The HALT process used at Rockwell Automation takes a product, printed circuit board, or component through five test sequences: low-temperature step-stress, high temperature step-stress, random vibration step-stress, combined temperature cycling/random vibration, and rapid temperature cycling. The temperature or vibration amplitude where any anomaly occurs, as well as the time, relative to the start of the test sequence, is noted. For each anomaly that occurs, a temperature and vibration robustness factor is calculated. The robustness factor is then translated to a probability of occurrence. Additionally, the severity of each anomaly is independently evaluated by engineering and quality functions in terms of severity of the effect on warranty, operation, and safety. The independent severity assessments are then combined into a composite severity. Recommended actions for remediation of each anomaly are made based on the occurrence and severity assessments using a HALT Action Matrix. This anomaly assessment process has eliminated the emotional arguments between various functions about remediating HALT anomalies and has ultimately benefitted the customer as more anomalies are being fixed than before the HALT Action Assessment process and tool were introduced.
{"title":"Taking the (emotional) stress out of HALT","authors":"G. Morris","doi":"10.1109/RAM.2017.7889745","DOIUrl":"https://doi.org/10.1109/RAM.2017.7889745","url":null,"abstract":"The HALT process used at Rockwell Automation takes a product, printed circuit board, or component through five test sequences: low-temperature step-stress, high temperature step-stress, random vibration step-stress, combined temperature cycling/random vibration, and rapid temperature cycling. The temperature or vibration amplitude where any anomaly occurs, as well as the time, relative to the start of the test sequence, is noted. For each anomaly that occurs, a temperature and vibration robustness factor is calculated. The robustness factor is then translated to a probability of occurrence. Additionally, the severity of each anomaly is independently evaluated by engineering and quality functions in terms of severity of the effect on warranty, operation, and safety. The independent severity assessments are then combined into a composite severity. Recommended actions for remediation of each anomaly are made based on the occurrence and severity assessments using a HALT Action Matrix. This anomaly assessment process has eliminated the emotional arguments between various functions about remediating HALT anomalies and has ultimately benefitted the customer as more anomalies are being fixed than before the HALT Action Assessment process and tool were introduced.","PeriodicalId":138871,"journal":{"name":"2017 Annual Reliability and Maintainability Symposium (RAMS)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127936436","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}
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