Pub Date : 2000-01-24DOI: 10.1109/RAMS.2000.816314
S. Jawaid, J. Ferguson
Accelerated reliability stress tests were performed to evaluate a design concern on a printed circuit board assembly (PCBA) for a disk drive product. Preliminary design tests indicated that a motor driver 176 pin PQFP (plastic quad flat package) IC package mounted on the PCBA may have a reliability problem in the field. The function of the motor driver chip was to provide electrical contact to the motor bearing assembly housed in the HDA. An elastomeric connector mounted on the PCBA under the 176 pin PQFP IC package was used to provide the electrical connection between the IC and the motor bearing assembly. A minimum force was required to maintain the electrical contact through the imbedded wires used in the elastomeric connector sandwiched between the PQFP package and the HDA. This force was provided by a hold down screw used to push the PCBA on the HDA. The reliability concern was that pin 1 and pin 176 on the corner of the PQFP package and closest to the elastomeric connector will break due to the high bending stress experienced, the effect of which is aggravated due to the coupling of thermal stress during operation. Typically stresses are higher on the four corner pins of an IC package, and gradually reduce to zero towards the middle of the package on each side. Accelerated reliability stress tests were performed to answer the reliability concerns, and if there was indeed a reliability issue, recommend design solutions to the problem and finally predict fatigue life.
{"title":"Design evaluation and product reliability assessment using accelerated reliability fatigue life tests","authors":"S. Jawaid, J. Ferguson","doi":"10.1109/RAMS.2000.816314","DOIUrl":"https://doi.org/10.1109/RAMS.2000.816314","url":null,"abstract":"Accelerated reliability stress tests were performed to evaluate a design concern on a printed circuit board assembly (PCBA) for a disk drive product. Preliminary design tests indicated that a motor driver 176 pin PQFP (plastic quad flat package) IC package mounted on the PCBA may have a reliability problem in the field. The function of the motor driver chip was to provide electrical contact to the motor bearing assembly housed in the HDA. An elastomeric connector mounted on the PCBA under the 176 pin PQFP IC package was used to provide the electrical connection between the IC and the motor bearing assembly. A minimum force was required to maintain the electrical contact through the imbedded wires used in the elastomeric connector sandwiched between the PQFP package and the HDA. This force was provided by a hold down screw used to push the PCBA on the HDA. The reliability concern was that pin 1 and pin 176 on the corner of the PQFP package and closest to the elastomeric connector will break due to the high bending stress experienced, the effect of which is aggravated due to the coupling of thermal stress during operation. Typically stresses are higher on the four corner pins of an IC package, and gradually reduce to zero towards the middle of the package on each side. Accelerated reliability stress tests were performed to answer the reliability concerns, and if there was indeed a reliability issue, recommend design solutions to the problem and finally predict fatigue life.","PeriodicalId":178321,"journal":{"name":"Annual Reliability and Maintainability Symposium. 2000 Proceedings. International Symposium on Product Quality and Integrity (Cat. No.00CH37055)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121947567","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 : 2000-01-24DOI: 10.1109/RAMS.2000.816329
N. Wattanapongsakorn, S. Levitan
In this research, we are developing a design framework for integrating dependability analysis into the distributed, heterogeneous, fault-tolerant real-time system design process. We focus on two dependability attributes: reliability and availability. We are implementing this framework on top of existing systems for the design of distributed, real-time systems such as TimeWiz. This will allow system designers to evaluate system dependability, while other system evaluation concerns, such as system performance and design cost, are analyzed during every step in the system design process. Our system dependability analysis provides choices of system design based on the dependability results. In addition, we perform system dependability evaluation, or optimization, early in the system design process, without needing complete design information. In other words, with incomplete design information, we are able to predict the behavior of system dependability. This will significantly reduce the time and costs of real-time system design.
{"title":"Integrating dependability analysis into the real-time system design process","authors":"N. Wattanapongsakorn, S. Levitan","doi":"10.1109/RAMS.2000.816329","DOIUrl":"https://doi.org/10.1109/RAMS.2000.816329","url":null,"abstract":"In this research, we are developing a design framework for integrating dependability analysis into the distributed, heterogeneous, fault-tolerant real-time system design process. We focus on two dependability attributes: reliability and availability. We are implementing this framework on top of existing systems for the design of distributed, real-time systems such as TimeWiz. This will allow system designers to evaluate system dependability, while other system evaluation concerns, such as system performance and design cost, are analyzed during every step in the system design process. Our system dependability analysis provides choices of system design based on the dependability results. In addition, we perform system dependability evaluation, or optimization, early in the system design process, without needing complete design information. In other words, with incomplete design information, we are able to predict the behavior of system dependability. This will significantly reduce the time and costs of real-time system design.","PeriodicalId":178321,"journal":{"name":"Annual Reliability and Maintainability Symposium. 2000 Proceedings. International Symposium on Product Quality and Integrity (Cat. No.00CH37055)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129687426","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 : 2000-01-24DOI: 10.1109/RAMS.2000.816276
D. Twigg, A. V. Ramesh, U.R. Sandadi, T. Sharma
A method is given for constructing fault tree gates to model mutually exclusive events. The gates are constructed from stochastically independent events, AND gates and NOT gates. Examples are presented to illustrate the technique. If the gate construction must be performed manually, the method adds complexity to the fault tree model that may not be justified. Approximating mutually exclusive events by independent events may have little effect on computed gate probabilities. The method could easily be automated in a standard fault tree solver so that this gate construction goes on behind the scenes. This would permit users to specify disjoint events directly. The authors conjecture that the additional computational cost would be small, since the number of basic events in the tree does not increase and the new NOT gates are inserted at the bottom of the tree.
{"title":"Modeling mutually exclusive events in fault trees","authors":"D. Twigg, A. V. Ramesh, U.R. Sandadi, T. Sharma","doi":"10.1109/RAMS.2000.816276","DOIUrl":"https://doi.org/10.1109/RAMS.2000.816276","url":null,"abstract":"A method is given for constructing fault tree gates to model mutually exclusive events. The gates are constructed from stochastically independent events, AND gates and NOT gates. Examples are presented to illustrate the technique. If the gate construction must be performed manually, the method adds complexity to the fault tree model that may not be justified. Approximating mutually exclusive events by independent events may have little effect on computed gate probabilities. The method could easily be automated in a standard fault tree solver so that this gate construction goes on behind the scenes. This would permit users to specify disjoint events directly. The authors conjecture that the additional computational cost would be small, since the number of basic events in the tree does not increase and the new NOT gates are inserted at the bottom of the tree.","PeriodicalId":178321,"journal":{"name":"Annual Reliability and Maintainability Symposium. 2000 Proceedings. International Symposium on Product Quality and Integrity (Cat. No.00CH37055)","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128606498","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 : 2000-01-24DOI: 10.1109/RAMS.2000.816310
A. Mettas
During the design phase of a product, reliability engineers are called upon to evaluate the reliability of the system. The question of how to meet a reliability goal for the system arises when the estimated reliability is inadequate. This then becomes a reliability allocation problem at the component level. In this paper, a general model estimates the minimum reliability requirement for multiple components within a system that will yield the goal reliability value for the system. The model consists of two parts. The first part is a nonlinear programming formulation of the allocation problem. The second part is a cost function formulation to be used in the nonlinear programming algorithm. A general behavior of the cost as a function of a component's reliability is assumed for this matter. The system's cost is then minimized by solving for an optimum component reliability, which satisfies the system's reliability goal requirement. Once the reliability requirement for each component is estimated, one can then decide whether to achieve this reliability by fault tolerance or fault avoidance. The model has yielded very encouraging results and it can be applied to any type of system, simple or complex, and for a variety of distributions. The advantage of this model is that it is very flexible, and requires very little processing time. These advantages make the proposed reliability allocation solution a great system design tool. A computer program has been developed and the model is available in a commercial software package called BlockSim/sup TM/.
{"title":"Reliability allocation and optimization for complex systems","authors":"A. Mettas","doi":"10.1109/RAMS.2000.816310","DOIUrl":"https://doi.org/10.1109/RAMS.2000.816310","url":null,"abstract":"During the design phase of a product, reliability engineers are called upon to evaluate the reliability of the system. The question of how to meet a reliability goal for the system arises when the estimated reliability is inadequate. This then becomes a reliability allocation problem at the component level. In this paper, a general model estimates the minimum reliability requirement for multiple components within a system that will yield the goal reliability value for the system. The model consists of two parts. The first part is a nonlinear programming formulation of the allocation problem. The second part is a cost function formulation to be used in the nonlinear programming algorithm. A general behavior of the cost as a function of a component's reliability is assumed for this matter. The system's cost is then minimized by solving for an optimum component reliability, which satisfies the system's reliability goal requirement. Once the reliability requirement for each component is estimated, one can then decide whether to achieve this reliability by fault tolerance or fault avoidance. The model has yielded very encouraging results and it can be applied to any type of system, simple or complex, and for a variety of distributions. The advantage of this model is that it is very flexible, and requires very little processing time. These advantages make the proposed reliability allocation solution a great system design tool. A computer program has been developed and the model is available in a commercial software package called BlockSim/sup TM/.","PeriodicalId":178321,"journal":{"name":"Annual Reliability and Maintainability Symposium. 2000 Proceedings. International Symposium on Product Quality and Integrity (Cat. No.00CH37055)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130530352","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 : 2000-01-24DOI: 10.1109/RAMS.2000.816284
C. Elks, J. Bechta Dugan, B.W. Johnson
Hard real-time systems can fail catastrophically if their control input is not updated before the real-time deadline is reached. A faulty controller in a hard real-time system may either fail to deliver the appropriate controller outputs to the plant for one or more sampling periods or it may generate erroneous controller outputs to the plant. Both instances result in what is known as dynamic failure, that is, the system becomes unstable, which may result in catastrophic damage to the plant. For applications where high integrity or dependability is required, it is important to assess the impact of dynamic failure on the overall reliability of the system. Leveraging concepts from system control theory, we now know that it is possible for a system to survive some temporary controller malfunctions because of plant dynamics. The authors present a real-time reliability model that elaborates relationship between the fault/error processes, recovery process and the deadline of a real-time control system. To ascertain the effects of the real-time deadline of the system, they review a technique for deriving the real-time deadlines for a class of linear time invariant control systems. This deadline information is then incorporated into the real-time reliability model, and the probability of dynamic failure is calculated. Finally, they give a example of deriving the deadline for a application, and evaluating the effect dynamic failure has on the system reliability.
{"title":"Reliability analysis of hard real-time systems in the presence of controller malfunctions","authors":"C. Elks, J. Bechta Dugan, B.W. Johnson","doi":"10.1109/RAMS.2000.816284","DOIUrl":"https://doi.org/10.1109/RAMS.2000.816284","url":null,"abstract":"Hard real-time systems can fail catastrophically if their control input is not updated before the real-time deadline is reached. A faulty controller in a hard real-time system may either fail to deliver the appropriate controller outputs to the plant for one or more sampling periods or it may generate erroneous controller outputs to the plant. Both instances result in what is known as dynamic failure, that is, the system becomes unstable, which may result in catastrophic damage to the plant. For applications where high integrity or dependability is required, it is important to assess the impact of dynamic failure on the overall reliability of the system. Leveraging concepts from system control theory, we now know that it is possible for a system to survive some temporary controller malfunctions because of plant dynamics. The authors present a real-time reliability model that elaborates relationship between the fault/error processes, recovery process and the deadline of a real-time control system. To ascertain the effects of the real-time deadline of the system, they review a technique for deriving the real-time deadlines for a class of linear time invariant control systems. This deadline information is then incorporated into the real-time reliability model, and the probability of dynamic failure is calculated. Finally, they give a example of deriving the deadline for a application, and evaluating the effect dynamic failure has on the system reliability.","PeriodicalId":178321,"journal":{"name":"Annual Reliability and Maintainability Symposium. 2000 Proceedings. International Symposium on Product Quality and Integrity (Cat. No.00CH37055)","volume":"213 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132021689","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 : 2000-01-24DOI: 10.1109/RAMS.2000.816302
G. Alstead, J. Moss, D. Kiang, V. Loll, D. Mahy
The intent of this session is to present the current status of the IEC Dependability Technical Committee and its plans for the future. To do this an able and experienced group of TC56 participants has been assembled to provide views on how TC56 is facing the challenges of the new millenium. Although TC 56 representatives have appeared regularly at past RAMS the notion of Dependability is still not well established in the US. It will be useful therefore to review the official defmition:
{"title":"IEC dependability standards in the new millennium panel","authors":"G. Alstead, J. Moss, D. Kiang, V. Loll, D. Mahy","doi":"10.1109/RAMS.2000.816302","DOIUrl":"https://doi.org/10.1109/RAMS.2000.816302","url":null,"abstract":"The intent of this session is to present the current status of the IEC Dependability Technical Committee and its plans for the future. To do this an able and experienced group of TC56 participants has been assembled to provide views on how TC56 is facing the challenges of the new millenium. Although TC 56 representatives have appeared regularly at past RAMS the notion of Dependability is still not well established in the US. It will be useful therefore to review the official defmition:","PeriodicalId":178321,"journal":{"name":"Annual Reliability and Maintainability Symposium. 2000 Proceedings. International Symposium on Product Quality and Integrity (Cat. No.00CH37055)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126386474","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 : 2000-01-24DOI: 10.1109/RAMS.2000.816312
C. Vassiliadis, M. G. Vassiliadou, L. Papageorgiou, E. Pistikopoulos
The derivation of optimal production and optimal maintenance plans in multi-purpose process plants are dynamically interacting problems which cannot be treated independent of one another, especially since in the event of equipment failure the execution of processing tasks can be transfered to other suitable multi-purpose equipment. In this work, a general optimization framework is proposed incorporating both the maintenance as well as the production planning model and providing the necessary links to quantify the strong interactions between them. As an example, the problem of optimally allocating maintenance crews to different equipment components over different operating periods is examined. In this case, the maintenance model corresponds to a continuous time Markov chain which is integrated and simultaneously optimized with the production planning model to provide the optimal maintainability and production patterns. The comparison of the solution against a traditional approach, in which detailed process considerations are not taken into account, clearly illustrates the advantages of the proposed methodology.
{"title":"Simultaneous maintenance considerations and production planning in multi-purpose plants","authors":"C. Vassiliadis, M. G. Vassiliadou, L. Papageorgiou, E. Pistikopoulos","doi":"10.1109/RAMS.2000.816312","DOIUrl":"https://doi.org/10.1109/RAMS.2000.816312","url":null,"abstract":"The derivation of optimal production and optimal maintenance plans in multi-purpose process plants are dynamically interacting problems which cannot be treated independent of one another, especially since in the event of equipment failure the execution of processing tasks can be transfered to other suitable multi-purpose equipment. In this work, a general optimization framework is proposed incorporating both the maintenance as well as the production planning model and providing the necessary links to quantify the strong interactions between them. As an example, the problem of optimally allocating maintenance crews to different equipment components over different operating periods is examined. In this case, the maintenance model corresponds to a continuous time Markov chain which is integrated and simultaneously optimized with the production planning model to provide the optimal maintainability and production patterns. The comparison of the solution against a traditional approach, in which detailed process considerations are not taken into account, clearly illustrates the advantages of the proposed methodology.","PeriodicalId":178321,"journal":{"name":"Annual Reliability and Maintainability Symposium. 2000 Proceedings. International Symposium on Product Quality and Integrity (Cat. No.00CH37055)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130126244","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 : 2000-01-24DOI: 10.1109/RAMS.2000.816327
B. Hauge, A. M. Stevens, R. J. Loomis, A. Ghose
In the USA, there is a corporate commitment to rationally and optimally apply reliability-centered maintenance to all aspects of maintenance on flight hardware, facilities and ground support equipment for the Space Shuttle Program. Towards this end, an RCM functional policy has been developed, and implementation plans, expertise development and consolidation, wide-ranging training of personnel and various RCM pilot demonstration projects are underway. A robust foundation and infrastructure for adopting, applying and continuously improving RCM in all its maintenance activities is being built. This bold, proactive approach to adopting the most progressive maintenance strategies available today is consistent with USA's overall goal to lead the way in safe and economical space exploration.
{"title":"Reliability-centered maintenance on the Space Shuttle Program","authors":"B. Hauge, A. M. Stevens, R. J. Loomis, A. Ghose","doi":"10.1109/RAMS.2000.816327","DOIUrl":"https://doi.org/10.1109/RAMS.2000.816327","url":null,"abstract":"In the USA, there is a corporate commitment to rationally and optimally apply reliability-centered maintenance to all aspects of maintenance on flight hardware, facilities and ground support equipment for the Space Shuttle Program. Towards this end, an RCM functional policy has been developed, and implementation plans, expertise development and consolidation, wide-ranging training of personnel and various RCM pilot demonstration projects are underway. A robust foundation and infrastructure for adopting, applying and continuously improving RCM in all its maintenance activities is being built. This bold, proactive approach to adopting the most progressive maintenance strategies available today is consistent with USA's overall goal to lead the way in safe and economical space exploration.","PeriodicalId":178321,"journal":{"name":"Annual Reliability and Maintainability Symposium. 2000 Proceedings. International Symposium on Product Quality and Integrity (Cat. No.00CH37055)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131238709","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 : 2000-01-24DOI: 10.1109/RAMS.2000.816332
J. Tillack, L. M. Kaufman, K. Kannan, B.W. Johnson
The functional requirements for an analog safety-critical system are typically similar to those found in its replacement digital system. However, the overall system specifications, especially those regarding maintenance and testability, must drastically change to accommodate the new digital technology. Attempting to re-create a digital version of the current analog safety system without making significant modifications is not a reasonable goal. Such a reverse engineering process only serves to increase the number of system failure modes by adding digital failure modes to the existing system. In addition, a reverse engineering process fails to take advantage of the true capabilities of digital technology. A safe and effective digital retrofit can be accomplished by ensuring the modification design process includes complete execution of all design steps beginning with the requirements phase.
{"title":"Design standards and their application to the digital retrofit of existing analog safety-critical systems","authors":"J. Tillack, L. M. Kaufman, K. Kannan, B.W. Johnson","doi":"10.1109/RAMS.2000.816332","DOIUrl":"https://doi.org/10.1109/RAMS.2000.816332","url":null,"abstract":"The functional requirements for an analog safety-critical system are typically similar to those found in its replacement digital system. However, the overall system specifications, especially those regarding maintenance and testability, must drastically change to accommodate the new digital technology. Attempting to re-create a digital version of the current analog safety system without making significant modifications is not a reasonable goal. Such a reverse engineering process only serves to increase the number of system failure modes by adding digital failure modes to the existing system. In addition, a reverse engineering process fails to take advantage of the true capabilities of digital technology. A safe and effective digital retrofit can be accomplished by ensuring the modification design process includes complete execution of all design steps beginning with the requirements phase.","PeriodicalId":178321,"journal":{"name":"Annual Reliability and Maintainability Symposium. 2000 Proceedings. International Symposium on Product Quality and Integrity (Cat. No.00CH37055)","volume":" 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132227297","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 : 2000-01-24DOI: 10.1109/RAMS.2000.816277
L. Meshkat, J. Bechta Dugan, J. Andrews
An approach for the reliability analysis of systems with on demand and dynamic failure modes is presented. Safety systems such as sprinkler systems or other protection systems are characterized by such failure behavior. They have support subsystems to start up the system on demand, and once they start running, they are prone to dynamic failure. Failure on demand requires an availability analysis of components (typically electromechanical components) which are required to start or support the safety system. Once the safety system is started, it is often reasonable to assume that these support components do not fail while running. Further, these support components may be tested and maintained periodically while not in active use. Dynamic failure refers to the failure while running (once started) of the active components of the safety system. These active components may be fault tolerant and utilize spares or other forms of redundancy, but are not maintainable while in use. In this paper, the authors describe a simple yet powerful approach to combining the availability analysis of the static components with a reliability analysis of the dynamic components. This approach is explained using a hypothetical example sprinkler system, and applied to a water deluge system taken from the offshore industry. The approach is implemented in the fault tree analysis software package, Galileo.
{"title":"Analysis of safety systems with on-demand and dynamic failure modes","authors":"L. Meshkat, J. Bechta Dugan, J. Andrews","doi":"10.1109/RAMS.2000.816277","DOIUrl":"https://doi.org/10.1109/RAMS.2000.816277","url":null,"abstract":"An approach for the reliability analysis of systems with on demand and dynamic failure modes is presented. Safety systems such as sprinkler systems or other protection systems are characterized by such failure behavior. They have support subsystems to start up the system on demand, and once they start running, they are prone to dynamic failure. Failure on demand requires an availability analysis of components (typically electromechanical components) which are required to start or support the safety system. Once the safety system is started, it is often reasonable to assume that these support components do not fail while running. Further, these support components may be tested and maintained periodically while not in active use. Dynamic failure refers to the failure while running (once started) of the active components of the safety system. These active components may be fault tolerant and utilize spares or other forms of redundancy, but are not maintainable while in use. In this paper, the authors describe a simple yet powerful approach to combining the availability analysis of the static components with a reliability analysis of the dynamic components. This approach is explained using a hypothetical example sprinkler system, and applied to a water deluge system taken from the offshore industry. The approach is implemented in the fault tree analysis software package, Galileo.","PeriodicalId":178321,"journal":{"name":"Annual Reliability and Maintainability Symposium. 2000 Proceedings. International Symposium on Product Quality and Integrity (Cat. No.00CH37055)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134182239","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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