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Li, J.-P., and G. Thompson. "Mechanical failure analysis in a virtual reality environment." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 219, no. 3 (August 1, 2005): 237–50. http://dx.doi.org/10.1243/095440805x28258.
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This paper is part of a research theme to develop methods that enhance risk assessment studies by the use of ‘automated’ failure analysis. The paper presents an approach to mechanical failure analysis and introduces a mechanical failure analysis module that can be used in a virtual reality (VR) environment. The module is used to analyse and predict failures in mechanical assemblies; it considers stress related failures within components, as well as failures due to component interactions. Mechanical failures are divided into two categories in this paper: material failures and interference failures. The former occur in components and the latter happen at the interface between components. Individual component failures can be analysed readily; a contribution of the mechanical failure analysis module is to predict interference failures. A mechanical failure analysis system that analyses and visualizes mechanical failures in a virtual environment has been developed. Two case studies demonstrate how the system carries out failure analysis and visualization as design parameters are changed.
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Zhang, Wen Guang, and Guo Min Lin. "Analysis of Aircraft Hydraulic System Failures." Advanced Materials Research 989-994 (July 2014): 2947–50. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.2947.
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The hydraulic system of Aircraft is an important power organization and plays an important role in the process of airplane operation. The failures of the airplane have the character of concealment, complexity and uncertainty. So if the hydraulic system ran out of order it not only cause huge casualties and economic losses, but also has a long and low efficiency maintenance cycle. This text analyzes the common causes of the failures and the failures that newly appeared of the aircraft hydraulic systems in detailed. Some of effective solutions have been proposed which quicken accelerate the speed of fault diagnosis and improve the efficiency of aircraft maintenance.
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Vizentin, Goran, Goran Vukelic, Lech Murawski, Naman Recho, and Josip Orovic. "Marine Propulsion System Failures—A Review." Journal of Marine Science and Engineering 8, no. 9 (August 27, 2020): 662. http://dx.doi.org/10.3390/jmse8090662.
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Failures of marine propulsion components or systems can lead to serious consequences for a vessel, cargo and the people onboard a ship. These consequences can be financial losses, delay in delivery time or a threat to safety of the people onboard. This is why it is necessary to learn about marine propulsion failures in order to prevent worst-case scenarios. This paper aims to provide a review of experimental, analytical and numerical methods used in the failure analysis of ship propulsion systems. In order to achieve that, the main causes and failure mechanisms are described and summarized. Commonly used experimental, numerical and analytical tools for failure analysis are given. Most indicative case studies of ship failures describe where the origin of failure lies in the ship propulsion failures (i.e., shaft lines, crankshaft, bearings, foundations). In order to learn from such failures, a holistic engineering approach is inevitable. This paper tries to give suggestions to improve existing design procedures with a goal of producing more reliable propulsion systems and taking care of operational conditions.
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Zhao, Lin, Krishnaiyan Thulasiraman, Xiaocheng Ge, and Ru Niu. "Failure Propagation Modeling and Analysis via System Interfaces." Mathematical Problems in Engineering 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/8593612.
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Safety-critical systems must be shown to be acceptably safe to deploy and use in their operational environment. One of the key concerns of developing safety-critical systems is to understand how the system behaves in the presence of failures, regardless of whether that failure is triggered by the external environment or caused by internal errors. Safety assessment at the early stages of system development involves analysis of potential failures and their consequences. Increasingly, for complex systems, model-based safety assessment is becoming more widely used. In this paper we propose an approach for safety analysis based on system interface models. By extending interaction models on the system interface level with failure modes as well as relevant portions of the physical system to be controlled, automated support could be provided for much of the failure analysis. We focus on fault modeling and on how to compute minimal cut sets. Particularly, we explore state space reconstruction strategy and bounded searching technique to reduce the number of states that need to be analyzed, which remarkably improves the efficiency of cut sets searching algorithm.
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TODINOV, M. T. "RELIABILITY ANALYSIS OF COMPLEX SYSTEMS BASED ON THE LOSSES FROM FAILURES." International Journal of Reliability, Quality and Safety Engineering 13, no. 02 (April 2006): 127–48. http://dx.doi.org/10.1142/s0218539306002161.
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The conventional reliability analysis is based on the premise that increasing the reliability of a system will decrease the losses from failures. In this paper it is demonstrated that increasing the reliability of the system does not always mean decreasing the losses from failures. An inappropriate increase of the reliability of the system may lead to a simultaneous increase of the losses from failure. In other words, a system reliability improvement, which is disconnected from the losses from failure does not necessarily reduce the losses from failures. An efficient discrete-event simulation model and algorithm have been proposed for reliability analysis based on the losses from failure for production systems with complex topology. The model links reliability with losses from failures. A new algorithm has also been developed for system reliability analysis related to productions systems based on multiple production units where the absence of critical failure means that at least m out n production units are working. The parametric study conducted on the basis of the developed models revealed that a dual-control production system is characterized by enhanced production availability, which increases with increasing the number of production units in the system. A production unit from a dual-control production system including multiple production units is characterized by a larger availability compared to a production unit from a dual-control production system including a single production unit. The proposed approach has been demonstrated by comparing the losses from failures and the net present values of two competing design topologies: one based on a single-channel control and the other based on a dual-channel control. The proposed models have been successfully applied and tested for reliability value analysis of productions systems in deepwater oil and gas production. It is also argued that the reliability allocation in a production system should be done to maximize the net profit/value obtained from the system. Consequently, a method for setting reliability requirements and reliability allocation maximizing the net profit by minimizing the sum of the capital costs and the expected losses from failures has been proposed. Reliability allocation which maximizes the net profit in case of a system consisting of blocks arranged in series is achieved by determining for each block individually, the reliabilities of the components which minimize the sum of the capital costs and the expected losses from failures.
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Li, Yifan, Hong-Zhong Huang, and Tingyu Zhang. "Reliability Analysis of C4ISR Systems Based on Goal-Oriented Methodology." Applied Sciences 11, no. 14 (July 8, 2021): 6335. http://dx.doi.org/10.3390/app11146335.
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Hard-and-software integrated systems such as command and control systems (C4ISR systems) are typical systems that are comprised of both software and hardware, the failures of such devices result from complicated common cause failures and common (or shared) signals that make classical reliability analysis methods will be not applicable. To this end, this paper applies the Goal-Oriented (GO) methodology to detailed analyze the reliability of a C4ISR system. The reliability as well as the failure probability of the C4ISR system, are reached based on the GO model constructed. At the component level, the reliability of units of the C4ISR system is computed. Importance analysis of failures of such a system is completed by the qualitative analysis capability of the GO model, by which critical failures of hardware failures like communication module failures and motherboard module failures as well as software failures like network module application software failures and decompression module software failures are ascertained. This method of this paper contributes to the reliability analysis of all hard-and-software integrated systems.
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Zuo, Lin, Tangfan Xiahou, and Yu Liu. "Evidential network-based failure analysis for systems suffering common cause failure and model parameter uncertainty." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 6 (June 27, 2018): 2225–35. http://dx.doi.org/10.1177/0954406218781407.
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The fault tree analysis has been extensively implemented in failure analysis of engineered systems. In most cases, the probabilities of basic events, e.g. components’ failures, are represented by crisp values in the fault tree analyses. However, due to lack of knowledge, scarcity of failure data, or vague judgments from experts, it may produce parameter uncertainty associated with degradation models of components/systems, and such model parameter uncertainty can be quantified by the epistemic uncertainty. In addition, the common cause failure, related to the simultaneous failures of two or more components caused by physical interactions or shared environments, often exists in advanced engineered systems and computing systems. In this paper, by considering both the common cause failure and the epistemic uncertainty associated with model parameters, an evidential network model embedded with common cause failure is proposed to facilitate system failure analysis. The detailed transformations from some logic gates of a fault tree to an evidential network model are given. Moreover, the conditional belief mass tables are constructed to quantify the dependency between the states of components and the entire system. An engineering case of an aero-engine oil system, together with comparative results, is presented to demonstrate the effectiveness of the proposed evidential network model.
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Cristaldi, Loredana, Mohamed Khalil, and Payam Soulatintork. "A root cause analysis and a risk evaluation of PV balance of system failures." ACTA IMEKO 6, no. 4 (December 28, 2017): 113. http://dx.doi.org/10.21014/acta_imeko.v6i4.425.
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<p>The Photovoltaic (PV) system is divided mainly into two subsystems; PV modules and a Balance of System (BoS) subsystems. This work shows two approaches for a reliability analysis on the subsystem level of aBoS: Failure mode effects criticality analysis (FMECA) and a Markov Process. FMECA concerns the root causes of failures and introduces prioritization numbers to highlight critical components of a BoS. Meanwhile, a Markov process is a reliability methodology that aims to predict the probability of success and failure of a BoS. In this way, a Markov process is a supportive tool for helping decision-makers to judge the criticality of failures associated with the operation of PV systems. Results show that the PV inverter contributes significantly to the failures of a BoS. Accordingly, further investigations are conducted on a PV inverter to prioritize the maintenance activities by determining the risk priority number of its component failures through quantitative CA. The novelty of the proposed methodologies stems from analyzing the roots of failure causes of BoS components and estimating the probability of failure of these components in order to improve the early development of a BoS, enhance maintenance management, and satisfy the demanding reliability by electric utilities.</p>
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Li, Jing Hua, and Wen Tao Yu. "Analysis and Design of Automatic Transmission’ Hydraulic System Based on Logic Analysis." Advanced Materials Research 945-949 (June 2014): 1611–14. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.1611.
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Volkswagen AG4 Automatic transmission ,for example , was detailed analyzed by logical method from the shifting operation, interlocking of combining elements and failure protection. Shifting operation must first meet the shifting demand ,mangy oil line criss-cross in the automatic transmission hydraulic system circuit ,in a particular gear ,some components must to be meet bonding requirements interlock between them ,finally ,vehicle need a failure system to protect the oil line to prevent failures in order to travel to the failure of the automatic transmission electronic control system .By analyzing ,design principles and ideas of automatic transmission shift controlling hydraulic system were derived.
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Elbadawi, I., M. A. Ashmawy, W. A. Yusmawiza, I. A. Chaudhry, N. B. Ali, and A. Ahmad. "Application of Failure Mode Effect and Criticality Analysis (FMECA) to a Computer Integrated Manufacturing (CIM) Conveyor Belt." Engineering, Technology & Applied Science Research 8, no. 3 (June 19, 2018): 3023–27. http://dx.doi.org/10.48084/etasr.2043.
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Fault finding and failure predicting techniques in manufacturing and production systems often involve forecasting failures, their effects, and occurrences. The majority of these techniques predict failures that may appear during the regular system production time. However, they do not estimate the failure modes and they require extensive source code instrumentation. In this study, we suggest an approach for predicting failure occurrences and modes during system production time intervals at the University of Hail (UoH). The aim of this project is to implement failure mode effect and criticality analysis (FMECA) on computer integrated manufacturing (CIM) conveyors to determine the effect of various failures on the CIM conveyor belt by ranking and prioritizing each failure according to its risk priority number (RPN). We incorporated the results of FMECA in the development of formal specifications of fail-safe CIM conveyor belt systems. The results show that the highest RPN values are for motor over current failure (450), conveyor chase of vibration (400), belt run off at the head pulley (200), accumulated dirt (180), and Bowed belt (150). The study concludes that performing FMECA is highly effective in improving CIM conveyor belt reliability and safety in the mechanical engineering workshop at UoH.
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Marquez, Andres, C. Jagroop, and C. Maharaj. "Wastewater collection system failures in a capital city: analysis and sustainable prevention." Water Science and Technology 83, no. 8 (March 19, 2021): 1958–72. http://dx.doi.org/10.2166/wst.2021.105.
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Abstract An analysis of failures in a capital city's wastewater collection system was carried out and recommendations were made for sustainable preventive measures based on a risk of failure assessment. Most failures in sewer lines were associated with blockage caused by sediment accumulation and clogging from fats, oils and/or grease dumped by restaurants along several streets, combined with poor or nonexistent maintenance of the lines. Sewer lines in streets with higher risk levels due to multiple food establishments along those streets experienced most of the failures. Sustainability of the proposed maintenance was evidenced since it reduces costs and exposure to harmful substances and hazardous conditions as well as minimizing environmental impacts.
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Ali, Nazakat, and Jang-Eui Hong. "Failure Detection and Prevention for Cyber-Physical Systems Using Ontology-Based Knowledge Base." Computers 7, no. 4 (December 6, 2018): 68. http://dx.doi.org/10.3390/computers7040068.
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Cyber-physical systems have emerged as a new engineering paradigm, which combine the cyber and physical world with comprehensive computational and analytical tools to solve complex tasks. In cyber-physical systems, components are developed to detect failures, prevent failures, or mitigate the failures of a system. Sensors gather real-time data as an input to the system for further processing. Therefore, the whole cyber-physical system depends on sensors to accomplish their tasks and the failure of one sensor may lead to the failure of the whole system. To address this issue, we present an approach that utilizes the Failure Modes, Effects, and Criticality Analysis, which is a prominent hazard analysis technique to increase the understanding of risk and failure prevention. In our approach, we transform the Failure Modes, Effects, and Criticality Analysis model into a UML(Unified Modeling Language) class diagram, and then a knowledge base is constructed based on the derived UML class diagram. Finally, the UML class diagram is used to build an ontology. The proposed approach employs a 5C architecture for smart industries for its systematic application. Lastly, we use a smart home case study to validate our approach.
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Hidaka, Toshimitsu. "Analysis of parallel redundant system with dependent failures." Electronics and Communications in Japan (Part III: Fundamental Electronic Science) 73, no. 4 (1990): 1–8. http://dx.doi.org/10.1002/ecjc.4430730401.
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Chen, Qiang, Yu Feng Guo, Na Pan, and Ji Lai Yu. "Probability Analysis Method of Power System Cascading Failures Caused by Extreme Hot Weather." Advanced Materials Research 860-863 (December 2013): 1996–2002. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.1996.
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In recent years, natural disasters happened frequently, which caused more and more failures of power system. To study the transmission lines failure under extreme hot weather, firstly the line's temperature changing with time is forecast based on the heat balance equation and the line's failure probability is calculated according to the historical statistics of failure rate. Then a test system to simulate the power grid under extreme hot weather is built and the curve of line's failure probability changing with time is obtained. The results provide a reference to power sector to guarantee the security and stability of the power grid.
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Li, Xiao Gang, Wei Han Wang, Wei Fang Zhang, and Yu Fan Wang. "Reliability Analysis on the Chassis Hydraulic System in Hydraulic Loader." Applied Mechanics and Materials 299 (February 2013): 35–37. http://dx.doi.org/10.4028/www.scientific.net/amm.299.35.
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Hydraulic loader is a major equipment for the airport engineering, the high efficient excavation is closely related to the reliability of equipment. Due to severe environment in the construction site, the chassis hydraulic system has high failure rate in the loader. Based on the criticality matrix analysis, some fatal failure modes were traced, including the leakage of motor, the pollution of hydraulic oil, the suction air of pump. Through the reliability prediction analysis, the estimated reliability of the chassis hydraulic system is 0.27, and mean time between failures of the system is 183h, in addition, critical components in the system are also determined. The above result could be used as reference for the optimization designing.
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Lv, Jia Hui, Wei Ze Wang, Shan Tung Tu, and Shao Wu Liu. "Failure Cases Analysis in Aerospace Field." Materials Science Forum 993 (May 2020): 1277–85. http://dx.doi.org/10.4028/www.scientific.net/msf.993.1277.
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The major concern in the aviation industry is the flight safety. Although great effort has been put into the development of material and system reliability, the failure cases of fatal accidents still occur nowadays. Due to the complexity of the aviation system and the interaction among the failure components, it is difficult to do the failure analysis of the related equipment. This study focused on surveying the failure cases in aviation, which were extracted from failure analysis journals, including Engineering Failure Analysis and Case studies in Engineering Failure Analysis, in order to obtain the failure sensitive factors or failure sensitive parts. The analytical results showed that among the failure cases the fatigue failure is the largest in number of occurrence. The most failed components are the disk, blade, landing gear, bearing, and fastener. The frequently failed materials are steel, aluminum alloy, superalloy and titanium alloy. Therefore, in order to assure the safety in aviation, more attention should be paid to the fatigue failures.
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Hu, Hui, Yu Peng Cao, and Pei Ning Li. "Failure Analysis of Thermocouple Thimble." Advanced Materials Research 197-198 (February 2011): 1785–90. http://dx.doi.org/10.4028/www.scientific.net/amr.197-198.1785.
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The failure analysis of a thermocouple thimble used in hydrogen pipeline of hydroforming cracking system is presented. In order to analyze the failure reason, detail checks and tests such as macroscopic check, chemical compositions analysis, residual stress test, mechanical property test, metallurgical structure and fracture analysis were carried out. Based on the results of investigation, the main causes of the failures are presented.
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Zhao, Ming. "Superposition of Power-Law Models for Hardware/Software System Reliability Data Analysis." International Journal of Reliability, Quality and Safety Engineering 10, no. 02 (June 2003): 121–30. http://dx.doi.org/10.1142/s0218539303001044.
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One of the widely used NHPP models in reliability is the so-called power-law model, also known as the Duane model. A power-law model can be applied in analyzing failure data of both software and hardware systems. Nevertheless, the power-law model is no longer applicable to describe the failure behavior when a hardware/software embedded system is concerned since the failures can come from both hardware and software. How to analyze the failure data of this type is still a problem to study and a new type of model is needed to develop. In this paper, we consider the superposition of the power-law models (SPLM) as one candidate to describe the failure behaviors of hardware/software systems. The characteristics of SPLMs are thoroughly studied. It is shown that an SPLM has the intensity function that can be increasing, decreasing, increasing-then-decreasing or decreasing-then-increasing. Specifically, the identification method of the superposition of power-law processes is provided by using the TTT-plot technique. The TTT-transform of a superposition of power-law processes is DFR-like. Therefore, the conditional TTT-plot should present a convex pattern if the system failures follow a superposition process by a few power-law processes. This provides us an easy way to identify the model when the testing data is available.
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SAXENA, AVINASH, and SHRISHA RAO. "DEGRADATION ANALYSIS OF PROBABILISTIC PARALLEL CHOICE SYSTEMS." International Journal of Reliability, Quality and Safety Engineering 21, no. 03 (June 2014): 1450012. http://dx.doi.org/10.1142/s0218539314500120.
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Degradation analysis is used to analyze the useful lifetimes of systems, their failure rates, and various other system parameters like mean time to failure (MTTF), mean time between failures (MTBF), and the system failure rate (SFR). In many systems, certain possible parallel paths of execution that have greater chances of success are preferred over others. Thus we introduce here the concept of probabilistic parallel choice. We use binary and n-ary probabilistic choice operators in describing the selections of parallel paths. These binary and n-ary probabilistic choice operators are considered so as to represent the complete system (described as a series-parallel system) in terms of the probabilities of selection of parallel paths and their relevant parameters. Our approach allows us to derive new and generalized formulae for system parameters like MTTF, MTBF, and SFR. We use a generalized exponential distribution, allowing distinct installation times for individual components, and use this model to derive expressions for such system parameters.
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Zhu, Pengyu, Jayantha Liyanage, and Simon Jeeves. "Data-driven failure analysis of emergency shutdown systems in oil and gas industry." Journal of Quality in Maintenance Engineering 26, no. 1 (June 12, 2019): 1–18. http://dx.doi.org/10.1108/jqme-03-2018-0022.
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Purpose Emergency shutdown (ESD) systems play a critical role in ensuring safety and availability of oil and gas production. The systems are operated in on-demand mode, and the detection and prediction of their failures is deemed challenging. The purpose of this paper is to develop a logical data-driven approach to enhance the understanding and detectability of ESD system failures. Design/methodology/approach The study was conducted in close collaboration with the Norwegian oil and gas industry. The study and analyses were supported by industrial data, failure data generated in a test facility in Norway and domain experts. Findings The paper demonstrated that there is a considerable potential to improve the decision process and to reduce the workload related to ESD systems by means of a logical data-driven approach. The results showed that the failure analysis process can be executed with more clarity and efficiency. Common cause failures could also be identified based on the suggested approach. The study further underlined the requirements regarding relevant data, new competence and technical supports in order to improve the current practice. Originality/value The paper leveraged the value of real-time data in identifying failures through mapping of the interrelationships between data, failure mechanisms and decisions. The failure analysis process was re-designed, and the understanding and decision making related to the system was improved as a result. The process developed for ESDs can further be adapted as a common practice for other low-demand systems.
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Lukas, Aditya, Ernest Mayr, Max Ruhri, Harald Katzmair, and Reinhard Perfler. "Failure Experience Improvement System (FEIS) for water supply systems." Journal of Hydroinformatics 14, no. 3 (November 7, 2011): 646–58. http://dx.doi.org/10.2166/hydro.2011.125.
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The Failure Experience Improvement System (FEIS) is a software tool that was developed in order to contribute to a minimization of hazardous events and failures within water supply systems and thus to achieve increased water safety. Based on the analysis of failure systems by applying Social Network Analysis (SNA) to the water supply infrastructure, the FEIS enables water utilities to identify causes and effects of failure events and to locate vulnerable points in their infrastructure. Failure events and the relations between them are the basis for the FEIS database. This database draws upon information on failure events which have occurred in practice at water utilities in Austria and on a literature review and survey of guidelines. The FEIS, which is accessed online, is currently used by six Austrian water utilities for development and test purposes. It provides both graphical visualization of the failure network and analytical indicators to evaluate failure events. In this way, it supports the utilities in identifying corrective actions in order to minimize the probability of failure occurrence and to limit the damage to the system once a failure has occurred.
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Fei, Juntao, Shuhao Chen, Gang Tao, and Suresh M. Joshi. "Robust Adaptive Control Scheme for Discrete-Time System With Actuator Failures." Journal of Dynamic Systems, Measurement, and Control 127, no. 3 (September 4, 2004): 520–26. http://dx.doi.org/10.1115/1.1978912.
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A robust adaptive control approach using output feedback for output tracking is developed for discrete-time linear time-invariant systems with uncertain failures of redundant actuators in the presence of the unmodeled dynamics and bounded output disturbance. Such actuator failures are characterized by some unknown inputs stuck at some unknown fixed values at unknown time instants. Technical issues such as plant-model output matching, adaptive controller structure, adaptive parameter update laws, stability and tracking analysis, and robustness of system performance are solved for the discrete-time adaptive actuator failure compensation problem. A case study is conducted for adaptive compensation of rudder servomechanism failures of a Boeing 747 dynamic model presented in discrete time, verifying the desired adaptive system performance in the presence of uncertain actuator failures.
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Kumar, Anuj, Sangeeta Pant, and S. B. Singh. "Availability and cost analysis of an engineering system involving subsystems in series configuration." International Journal of Quality & Reliability Management 34, no. 6 (June 5, 2017): 879–94. http://dx.doi.org/10.1108/ijqrm-06-2016-0085.
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Purpose The purpose of this paper is to evaluate various reliability measures like availability, reliability, mean time to failure and profit function. Design/methodology/approach The authors present a novel method for availability analysis of an engineering system incorporating waiting time to repair. The considered system consists of two subsystems, namely, A and B connected in series. The subsystem B has two identical units in standby arrangement. Each unit of the subsystem has two modes, i.e. normal efficiency or failed. The two standby units of the subsystem B are connected by an imperfect switching. The system is analyzed by supplementary variable technique, Laplace transformation and Gumbel-Hougaard family of copula. Findings Numerical examples with a way to highlight the important results have been appended at last. Numerical calculation shows that availability and reliability of the system is decreasing with respect to time when failure rates are fixed at different values. Finally, cost analysis of system reveals that the expected profit decreases with increase in service cost. Originality/value This paper presents a mathematical model in which an important aspect of switching has been taken into consideration, which is consistent with actual failures of switching by assuming two different types of failure between adjacent transition. It is evaluated with the help of the Gumbel-Hougaard family of copula.
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Gu, Haigang, Guang Feng, Yonggang Lin, and Chaozhu Wang. "Analysis of bearing failures in a typical high-power marine gearbox." Industrial Lubrication and Tribology 70, no. 1 (January 8, 2018): 33–41. http://dx.doi.org/10.1108/ilt-10-2016-0246.
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Purpose This paper aims to analyze fatigue failures of a typical marine gearbox under harsh ocean conditions, and these failures are reasonably attributed to the bearing fretting fatigue damages. Design/methodology/approach Two typical FAG cylindrical roller bearings mounted on this marine gearbox are particularly used for analysis, as they are most vulnerable to these failures. A series of simulations have also been conducted to verify the analysis results and failure reasons by reproducing the fretting fatigue damages for the same shaft-bearing system under the same manufacturing error conditions. Findings The analysis results indicate that manufacturing errors are the most possible reasons for the bearing failures, and these errors have more effects on the FAG cylindrical roller bearing as compared to other bearings mounted on the same shaft system. The simulations results are in good agreement with the theoretical analysis results and test results and hence validate that manufacturing errors are the dominant reasons for bearing fretting fatigue damages in this typical marine gearbox. Originality/value Fatigue failures of a typical marine gearbox. Manufacturing errors are the most possible reasons for the bearing failures. A series of simulations have been conducted to verify the analysis results and failure reasons. The simulations results are in good agreement with the theoretical analysis results and test results.
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Yu, Xingbin, and Chanan Singh. "Probabilistic power system security analysis considering protection failures." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 23, no. 1 (March 2004): 35–47. http://dx.doi.org/10.1108/03321640410507536.
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Price, C. J., J. E. Hunt, M. H. Lee, and A. R. T. Ormsby. "A Model-Based Approach to the Automation of Failure Mode Effects Analysis for Design." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 206, no. 4 (October 1992): 285–91. http://dx.doi.org/10.1243/pime_proc_1992_206_189_02.
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This paper describes the application of model-based technology in the area of failure mode effects analysis (FMEA). FMEA involves the repetitive application of engineering expertise, and so would seem to be a promising target for automation through knowledge-based systems (KBS) technology. However, in order to decide what would be the effect of a failure in a sub-system, it is necessary to reason about the structure of the sub-system being investigated and to be able to represent and reason about different facets of the way in which the sub-system works. The difficulty of automating this analysis of failure effects for new designs has meant that, in general, automation of the FMEA task has concentrated on only the clerical aspects of FMEA—helping the human expert to keep track of which possible failures have been analysed. The work described in this paper automates the analysis phase of the FMEA process. This should enable the development of computerized aids for the FMEA engineer which will eliminate much of the tediousness of the task.
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Abuelma'atti, Muhammad Taher, and Isa Salman Qamber. "Reliability and Availability Analysis of Some Systems with Common-Cause Failures Using SPICE Circuit Simulation Program." Active and Passive Electronic Components 22, no. 1 (1999): 31–49. http://dx.doi.org/10.1155/1999/12147.
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The effectiveness of SPICE circuit simulation program in calculating probabilities, reliability, steady-state availability and mean-time to failure of repairable systems described by Markov models is demonstrated. Two examples are presented. The first example is a warm standby system with common-cause failures and human errors. The second example is a non-identical unit parallel system with common-cause failures. In both cases recourse to numerical solution is inevitable to obtain the Laplace transforms of the probabilities. Results obtained using SPICE are compared with previously published results obtained using the Laplace transform method. Full SPICE listings are included.
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Chen, Mingxi, and Qinghui Jiang. "An early warning system integrating time-of-failure analysis and alert procedure for slope failures." Engineering Geology 272 (July 2020): 105629. http://dx.doi.org/10.1016/j.enggeo.2020.105629.
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Sitzenfrei, R., M. Mair, M. Möderl, and W. Rauch. "Cascade vulnerability for risk analysis of water infrastructure." Water Science and Technology 64, no. 9 (November 1, 2011): 1885–91. http://dx.doi.org/10.2166/wst.2011.813.
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One of the major tasks in urban water management is failure-free operation for at least most of the time. Accordingly, the reliability of the network systems in urban water management has a crucial role. The failure of a component in these systems impacts potable water distribution and urban drainage. Therefore, water distribution and urban drainage systems are categorized as critical infrastructure. Vulnerability is the degree to which a system is likely to experience harm induced by perturbation or stress. However, for risk assessment, we usually assume that events and failures are singular and independent, i.e. several simultaneous events and cascading events are unconsidered. Although failures can be causally linked, a simultaneous consideration in risk analysis is hardly considered. To close this gap, this work introduces the term cascade vulnerability for water infrastructure. Cascade vulnerability accounts for cascading and simultaneous events. Following this definition, cascade risk maps are a merger of hazard and cascade vulnerability maps. In this work cascade vulnerability maps for water distribution systems and urban drainage systems based on the ‘Achilles-Approach’ are introduced and discussed. It is shown, that neglecting cascading effects results in significant underestimation of risk scenarios.
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Gu, Chaoyang, Lin Zhai, Wei Gu, Yuyu Sun, Chengjing Han, Xianwen Zhou, and Wangqiang Niu. "System Analysis and Reliability Analysis for Environmental Test Chambers." International Journal of Circuits, Systems and Signal Processing 14 (January 12, 2021): 1115–28. http://dx.doi.org/10.46300/9106.2020.14.140.
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The purpose of this paper is to present the results of the application of various models to estimate the reliability of environmental test chambers, especially, the methodology proposed by the International Electrotechnical Commission (IEC), using the Homogeneous Poisson process (HPP) and Non-Homogeneous Poisson process (NHPP) models, is adopted first, and then, a non-monotonic trend test and bathtub curve intensity function not covered by IEC are used, and supplementary analysis is used to characterize the resulting failure intensity. For the first time, the stochastic process model was applied to evaluate the reliability of 20 environmental test chambers. The results show that the IEC standards process is suitable for the reliability evaluation of a single chamber, and 16 chambers conform to the HPP model and 4 chambers conform to the NHPP model. However, there is the power-law model (PLP) rejection cases among the overall description of multiple chambers by the IEC model. The rejected cases were analyzed again by using a non-monotonic trend test and constructing a double Weibull process tub curve strength function, and the 3-stage time interval of the bathtub curve failure is obtained, which is in line with the actual operation data. The Ward clustering method is used for the mean time between failures of 20 chambers, resulting in 4 types of chamber groups with different reliability values (71,52,100,130 days), which is of great significance for studying the reliability of the environmental test chamber and carrying out customized maintenance.
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Perry, B. T., E. J. Rothwell, and L. L. Nagy. "Analysis of switch failures in a self-structuring antenna system." IEEE Antennas and Wireless Propagation Letters 4 (2005): 68–70. http://dx.doi.org/10.1109/lawp.2005.844129.
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Fabis-Domagala, Joanna, Hassan Momeni, Mariusz Domagala, Grzegorz Filo, Saeed Bikass, and Pawel Lempa. "Matrix FMEA Analysis of the Flow Control Valve." Quality Production Improvement - QPI 1, no. 1 (July 1, 2019): 590–95. http://dx.doi.org/10.2478/cqpi-2019-0079.
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Abstract Reliability is a key feature in engineering systems and might be improved by using preventive methods, which allows for identification potential failures and establishing cause-and-effect relationships in consistent and systematic way. One of the popular quality improvement method is FMEA (Failure Modes and Effects Analysis). An application of matrix FMEA analysis method on example of flow control valve has been presented and discussed in the work. Presented example shows also a different ways of evaluating failures and theirs influence on analysis results.
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Hogan, P. A., C. R. Burrows, K. A. Edge, R. M. Atkinson, M. R. Montakhab, and D. J. Woollons. "Automated Fault Tree Analysis for Hydraulic Systems." Journal of Dynamic Systems, Measurement, and Control 118, no. 2 (June 1, 1996): 278–82. http://dx.doi.org/10.1115/1.2802315.
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Fault Tree Analysis is a commonly used technique for assessing the reliability and safety of engineering systems at the design stage but it is tedious and time-consuming to apply. A reconfigurable program is presented which utilizes a library of qualitative component models to enable fault tree type analyses of arbitrary hydraulic circuit configurations. It is applied to the analysis of failures of an experimental rig and a complex industrial system, and some features of its design and performance are discussed.
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Zhang, Xiao Nan, An Xin Liu, Qing Zhen Gao, Xing Qing, and Xing Chang. "Engineering Machinery Engine System Reliability Analysis." Advanced Materials Research 139-141 (October 2010): 2587–90. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.2587.
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It exists in complexity and fuzziness in structure and failure character of engineering machinery complex system. To solve the problem, fuzzy theory was introduced into fault tree analysis, and then the steps, principles and methods of fuzzy fault tree are determined. Based on the analysis of engineering machinery typical engine systemic structure and fault criterion, a fuzzy fault tree is established. Used a fuzzy mathematics method of reliability analysis with fuzzy fault rate and the median method of fuzzy significance analysis, the fuzzy fault rate and fuzzy significance of parts and subsystems is calculated. The result indicates that this method can solve the fuzziness problem of failure criterion and data in fault tree analysis. The result provides valuable reference for the reliability analysis.
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Rastayesh, Sima, Sajjad Bahrebar, Frede Blaabjerg, Dao Zhou, Huai Wang, and John Dalsgaard Sørensen. "A System Engineering Approach Using FMEA and Bayesian Network for Risk Analysis—A Case Study." Sustainability 12, no. 1 (December 20, 2019): 77. http://dx.doi.org/10.3390/su12010077.
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This paper uses a system engineering approach based on the Failure Mode and Effect Analysis (FMEA) methodology to do risk analysis of the power conditioner of a Proton Exchange Membrane Fuel Cell (PEMFC). Critical components with high risk, common cause failures and effects are identified for the power conditioner system as one of the crucial parts of the PEMFCs used for backup power applications in the telecommunication industry. The results of this paper indicate that the highest risk corresponds to three failure modes including high leakage current due to the substrate interface of the metal oxide semiconductor field effect transistor (MOSFET), current and electrolytic evaporation of capacitor, and thereby short circuit, loss of gate control, and increased leakage current due to gate oxide of the MOSFET. The MOSFETs, capacitors, chokes, and transformers are critical components of the power stage, which should be carefully considered in the development of the design production and implementation stage. Finally, Bayesian networks (BNs) are used to identify the most critical failure causes in the MOSFET and capacitor as they are classified from the FMEA as key items based on their Risk Priority Numbers (RPNs). As a result of BNs analyses, high temperature and overvoltage are distinguished as the most crucial failure causes. Consequently, it is recommended for designers to pay more attention to the design of MOSFETs’ failure due to high leakage current owing to substrate interface, which is caused by high temperature. The results are emphasizing design improvement in the material in order to be more resistant from high temperature.
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Pearman, Gordon R. "Automatic BusBar Transfer Switch Fault Tree Analysis." Marine Technology and SNAME News 34, no. 01 (January 1, 1997): 31–43. http://dx.doi.org/10.5957/mt1.1997.34.1.31.
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This paper discusses the application of an existing statistical analysis technique called "Fault Tree Analysis " to Automatic BusBar Transfer Switch failures on a new class of Naval Supply Ship. Fault Tree Analysis is a technique, used in many "High Technology Industries, " to pictorially display facts surrounding system, equipment or process failures. Technological complexity and safety concerns in the marine industry make it necessary to also use an organized technique to display facts affecting undesirable events, or failures, and their cause and effect.
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ZAMOJSKI, WOJCIECH, and DARIUSZ CABAN. "IMPACT OF SOFTWARE FAILURES ON THE RELIABILITY OF A MAN-COMPUTER SYSTEM." International Journal of Reliability, Quality and Safety Engineering 13, no. 02 (April 2006): 149–56. http://dx.doi.org/10.1142/s0218539306002173.
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Software failures and human errors are the most common reasons of inoparability of computer systems. Computers are increasingly reliable, but the level of transcient faults, caused by errors hidden in the programs, remains the same. For this reason software is becoming the key factor in the synthesis of highly reliable systems. Software errors do not result from operation, they either exist from the start or are inserted when patching or upgrading it. Some errors result from incorrect human interaction or unexpected environmental changes. Assessment of software impact requires functional-reliability approach to reliability analysis: the software fault occurs when it causes incorrect operation and not when it is introduced to the system. It is proposed to use software reliability models in system analysis, to predict the intensity of software faults. The software recovery after a failure is realized by restarts of various extend (microrestarts, minirestarts and macrorestarts). The impact of software failures and restarts on system availability is assessed.
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Andrews, J. D., and L. M. Ridley. "Reliability of sequential systems using the cause—consequence diagram method." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 215, no. 3 (August 1, 2001): 207–20. http://dx.doi.org/10.1177/095440890121500304.
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In many industrial systems, where safety is of the utmost importance, it is necessary that expedient tools for accident analysis are available and employed at the design stage. Such tools must be able to handle large systems in a systematic way and display the factors that are of vital importance for the functionality of the system. The technique of fault tree analysis (FTA) is commonly used to assess the failure probability of such systems. The fault tree represents the failure logic of the system in an inverted tree structure and has the advantage that it provides very good documentation of the way the failure logic was developed. Conventional fault tree quantification requires a number of assumptions regarding the system. One of these is that the basic events in the tree occur independently. This condition is not satisfied when sequential failures are encountered. Employing alternative methods, such as Markov methods, can result in the loss of the documentation that represents the failure logic of the system. The cause-consequence diagram method is a tool that, like fault tree analysis, documents the failure logic but has the extra capability enabling the analysis of systems subject to sequential failures. In addition, the cause-consequence diagram identifies the complete set of system responses to any given initiating event. This paper is concerned with the cause-consequence diagram method and its application to sequentially operating systems. It extends previous work by providing more rigorous guidelines to enable the construction of the diagram and an analysis methodology that can be used when dependencies exist between the events featured in the decision boxes. A new symbol distinguishing between events that exist at a specified point in time and those that occur at that time is introduced to facilitate the analysis.
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Thilmany, Jean. "Make No Mistake." Mechanical Engineering 131, no. 06 (June 1, 2009): 48–51. http://dx.doi.org/10.1115/1.2009-jun-5.
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This paper explains the concept of goof-proofing and its usefulness in engineering design. No standard design rules exist for engineers to follow in anticipation of human error. Human reliability analysis tools such as event trees and fault trees to model a human's contribution to events such as decreasing one's speed on an exit ramp. To minimize human error, engineering students color code wires and use specific prong configurations in the design of an automobile. It is observed that engineers follow failure modes and effects analysis procedures. The failure modes procedure isolates potential failures within a system or product. Effects analysis is the study of the consequences of those failures. The attitude on the part of designers is that they have the requisite knowledge, either from past projects or due to their expertise. The paper concludes that regardless of how engineers go about goof-proofing their designs, they must keep the end user in mind.
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Gupta, Sorabh. "Stochastic modelling and availability analysis of a critical engineering system." International Journal of Quality & Reliability Management 36, no. 5 (May 7, 2019): 782–96. http://dx.doi.org/10.1108/ijqrm-07-2018-0167.
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Purpose The purpose of this paper is to present the technique for evaluating the performance of a condensate system of a coal-based thermal power plant situated in the northern part of India. The data which used for system availability evaluation are not precise and are uncertain and, further, collected from concerned power plant history sheets and from discussion through plant personnel. Design/methodology/approach In the proposed model, traditional Markov birth-death process using a probabilistic approach is used to analyze the performance of a complex repairable condensate system of power plant up to a desired degree of accuracy. This approach has been demonstrated by breaking the condensate system into six subsystems arranged in series with two feasible states, namely, working and failed, labeled in a transition diagram and modeled as a Markov process, using Chapman–Kolmogorov equations, which are used for development of a probabilistic stochastic model for availability analysis in a more effecting manner, considering some suitable assumptions. Findings This study of analysis of reliability and availability can help in increasing the plant production and performance. The analysis is done with the help of availability matrices, which are developed using different combinations of failures and repair rates of all subsystems. To achieve the goal of maximum power generation, it is required to run the various subsystem of the concerned system of plant, failure free for a long duration. Therefore, the present approach may be a more powerful analysis tool to access the performance of all subsystems of a condensate system in terms of availability level achieved in availability matrices. The results of present study are found to be highly beneficial to the plant management for making maintenance decisions. Originality/value The present paper suggests a suitable technique for stochastic modeling and availability evaluation of an industrial system using Markovian approach and drawing a transition diagram to represent the operational behavior of the system. The present methodology includes the advantage of the ability to model and develop a more complex industrial system and helps in improving the performance and handling the uncertainties and possibilities of an industrial system.
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Melikyan, Alla. "THE RAILWAY INFORMATION SYSTEM AS A QUEUEING SYSTEM." TRANSPORT 24, no. 4 (December 31, 2009): 339–44. http://dx.doi.org/10.3846/1648-4142.2009.24.339-344.
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The present article dwells upon the Information System (IS) of Latvian railways providing the analysis of the queuing system (QS) used to removing defects occurring in the infinite linear queuing system. The author of the article analyzes research data about the failures of system functioning in order to establish the parameters of the before mentioned system and other information systems used by Latvian railways. The structure of accidents happening in the informative systems and the removal of possible defects are researched. The present investigation provides evidence that substantiates a Markov hypothesis about the peculiarities of IS service. The author also examines the organizational structure of IS taking into consideration the level of the danger of possible accidents. The statistics of the failures of IS relates to the statistics of accidents that might happen to rolling stock.
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Korving, H., and E. C. Ottenhoff. "Analysis of the causes of pump failure and differences of failure characteristics." Water Science and Technology 57, no. 8 (April 1, 2008): 1271–76. http://dx.doi.org/10.2166/wst.2008.304.
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It is generally accepted that sewage pumping stations are directly responsible for affecting sewer system performance in terms of combined sewer overflows and flooding. However, the specific causes of pump failure are unknown. This paper presents the analysis of pump failure data provided by four sewer management authorities in The Netherlands. Pump failures have been studied accounting for the nature of failures, operation and maintenance procedures of the management authority, ageing of the pumps and changes in the environment of pumps. Pumps have been clustered on the basis of specific characteristics of their ‘environment’, including pump age, operating time, pump capacity and degree of pollution of the sewage. The analysis shows that the well known ‘bathtub’ type failure rate curve can describe failures of sewage pumps. The impact of the degree of pollution of the sewage, however, is less clear. Operating time and total pumping capacity show no correlation with failure rate. Consequently, further research using data mining techniques is needed to separate the impact of the different aspects of the environment of a pump.
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Qi, Faqun, and Binghai Zhou. "Maintenance policy optimization for a cold standby system considering multiple failure types." Journal of Quality in Maintenance Engineering 25, no. 2 (May 7, 2019): 182–98. http://dx.doi.org/10.1108/jqme-09-2017-0065.
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Purpose The purpose of this paper is to develop novel preventive maintenance (PM) modeling methods for a cold standby system subject to two types of failures: random failure and deterioration failure. Design/methodology/approach The system consists of two components and a single repair shop, assuming that the repair shop can only service for one component at a time. Based on semi-Markov theory, transition probabilities between all possible system states are discussed. With the transition probabilities, Markov renewal equations are established at regenerative points. By solving the Markov regenerative equations, the mean time from the initial state to system failure (MTSF) and the steady state availability (SSA) are formulated as two reliability measures for different reliability requirements of systems. The optimal PM policies are obtained when MTSF and SSA are maximized. Findings The result of simulation experiments verifies that the derived maintenance models are effective. Sensitivity analysis revealed the significant influencing factors for optimal PM policy for cold standby systems when different system reliability indexes (i.e. MTSF and SSA) are considered. Furthermore, the results show that the repair for random failure has a tremendous impact on prolonging the MTSF of cold standby system and PM plays a greater role in promoting the system availability of a cold standby system than it does in prolonging the MTSF of system. Practical implications In practical situations, system not only suffers normal deterioration caused by internal factors, but also undergoes random failures influenced by random shocks. Therefore, multiple failure types are needed to be considered in maintenance modeling. The result of the sensitivity analysis has an instructional role in making maintenance decisions by different system reliability indexes (i.e. MTSF and SSA). Originality/value This paper presents novel PM modeling methods for a cold standby system subject to two types of failures: random failure and deterioration failure. The sensitivity analysis identifies the significant influencing factors for optimal maintenance policy by different system reliability indexes which are useful for the managers for further decision making.
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BASTIAN, Bartosz, Rafał GAWARKIEWICZ, and Michał WASILCZUK. "ANALYSIS OF THE POSSIBILITIES OF HIGH SPEED SHAFT BEARING SYSTEM DURABILITY INCREASE." Tribologia 267, no. 3 (June 30, 2016): 37–47. http://dx.doi.org/10.5604/01.3001.0010.7291.
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During the operation of wind turbines with a gearbox of traditional configuration, a high failure rate of high-speed shaft bearings is observed. Such a high failures frequency is not reflected in standard bearing durability calculation methods, which can be attributed to atypical failure mechanism. To avoid observed problems in the 1.5 MW wind turbine, the modification of the existing bearing system is proposed. Multiple options, utilizing various bearing types were investigated. Different versions were examined for a potential durability increase, the extent of necessary design modifications, and possibility of solving existing problems in operation.
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Hwang, Hwee, Kevin Lansey, and Daniel R. Quintanar. "Resilience-based failure mode effects and criticality analysis for regional water supply system." Journal of Hydroinformatics 17, no. 2 (September 30, 2014): 193–210. http://dx.doi.org/10.2166/hydro.2014.111.
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An alternative risk assessment method, known as failure mode effects and criticality analysis (FMECA), is demonstrated on the regional water supply systems (RWSS) in Tucson, AZ, USA that combines delivery of potable and reclaimed water and conveyance of wastewater to a developing area within the Tucson RWSS. The goal of FMECA is to examine the volumetric severity of a component failure on the overall system function by modeling the system under alternative failure modes. Within FMECA, the Risk Priority Number (RPN) is applied to compare the risk criticality between components' failures. To complete FMECA, the Tucson RWSS is represented in a network flow model that optimally allocates flows between sources and demand points to minimize operational costs. Potential failure mode consequences are evaluated from the flow model as the volume of water not delivered to users if the component is unavailable. The volumetric severity of the failure event is converted to an ordinal value using stakeholder judgment. Likelihood of each failure mode is similarly defined by stakeholders on a 1–10 scale. The RPN is then computed as the product of the severity and likelihood. RPN values for all failure modes are then ranked to assess the most critical elements. Alternative system configurations are examined to assess the value of redundancies on the Tucson RWSS resilience.
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FIONDELLA, LANCE. "RELIABILITY AND SENSITIVITY ANALYSIS OF COHERENT SYSTEMS WITH NEGATIVELY CORRELATED COMPONENT FAILURES." International Journal of Reliability, Quality and Safety Engineering 17, no. 05 (October 2010): 505–29. http://dx.doi.org/10.1142/s0218539310003913.
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Modeling correlated component failures poses a unique challenge for reliability researchers because it requires ingenuity to devise an approach free from the assumption that components fail in a statistically independent manner. Several studies have addressed this problem with models that introduce additional parameters to describe the correlated failure of components. However, these earlier techniques often require the correlations to be positive and almost always introduce an exponential number of correlation parameters. These restrictions limit the scalability of existing approaches for conducting sensitivity analysis on the correlation parameters, which could identify correlation reductions that would improve system reliability. This paper presents a technique for reliability and sensitivity analysis that requires only a quadratic number of correlation parameters, encompassing systems with both negative and positive component correlations. Unlike previous research, the proposed approach places no unnecessary restrictions on a system's correlation parameters. A series of examples illustrates the flexibility of the approach. The results quantitatively confirm that negative component correlation assists fault-tolerant systems to attain levels of reliability even higher than systems of statistically independent redundant components. Thus, the techniques introduced here offer a methodology to concisely measure the utility of negative component correlations on system reliability improvement.
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Lidoris, Georgios, Florian Rohrmüller, Dirk Wollherr, and Martin Buss. "System interdependence analysis for autonomous robots." International Journal of Robotics Research 30, no. 5 (January 17, 2011): 601–14. http://dx.doi.org/10.1177/0278364910393040.
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With the increasing complexity of robotic systems, system robustness and efficiency are harder to achieve, since they are determined by the interplay of all of a system’s components. In order to improve the robustness of such systems, it is essential to identify the system components that are crucial for each task and the extent to which they are affected by other components and the environment. Such knowledge will help developers to improve their systems, and can also be directly utilized by the systems themselves, for example, to detect failures and thereby correctly adjust the system’s behavior. In this article a method of system interdependence analysis is presented. The basic idea is to learn and quantitatively evaluate the coherence between performance indicators of different system components, as well as the influence of environmental parameters on the system. To validate the proposed approach, system interdependence analysis is applied to the navigation system of an autonomous mobile robot. Its navigational methods are presented and suitable indicators are derived. The results of using the method, based on experimental data from an extended field experiment, are given.
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Milioulis, Konstantinos, Victor Bolbot, and Gerasimos Theotokatos. "Model-Based Safety Analysis and Design Enhancement of a Marine LNG Fuel Feeding System." Journal of Marine Science and Engineering 9, no. 1 (January 11, 2021): 69. http://dx.doi.org/10.3390/jmse9010069.
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Recent regulatory requirements for shipping emissions control have led to the adoption of Liquefied Natural Gas (LNG) as a marine fuel and the design of LNG-fuelled vessels. Considering the potential safety implications due to system failure/unavailability, this study aims at the safety analysis of a low-pressure LNG fuel feeding system using a novel model-based methodology. The proposed methodology is based on the functional system modelling, leading to the failure diagrams development, and combines the use of Failure Modes, Effects, and Criticality Analysis (FMECA) and Fault Tree Analysis (FTA), which are performed in MADe™ and PTC Windchill software environments. The FMECA results are employed to identify the investigated system critical components and failures as well as specifying the top events for the subsequently performed FTA, which evaluates the top events failure rates. The system critical components identification leads to the system design modification targeting reduced safety metrics. This study results demonstrate that the evaporator, pressure build-up unit, sensors, and cryogenic valve assemblies are the most critical components of the investigated system, whilst the enhanced system design exhibits a failure rate reduced by 69% in comparison to the baseline system. This study reveals the advantages of the developed methodology along with some limitations of the employed tools and contributes to the quantitative safety analysis and design of ship complex systems.
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XING, LIUDONG, and SUPRASAD V. AMARI. "EFFECTIVE COMPONENT IMPORTANCE ANALYSIS FOR THE MAINTENANCE OF SYSTEMS WITH COMMON-CAUSE FAILURES." International Journal of Reliability, Quality and Safety Engineering 14, no. 05 (October 2007): 459–78. http://dx.doi.org/10.1142/s021853930700274x.
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In this paper, we consider the component importance analysis of coherent systems subject to common-cause failures. The purpose of component importance analysis is to obtain information regarding a component's contribution or importance to the system reliability. The results from the component importance analysis are key contributors to the system design, tuning, and maintenance activities. Various measures have been proposed for the component importance analysis, but little work has been done to compare their performance. In this research, we investigate and compare a set of nine existing importance measures and select the most informative and appropriate one for guiding the system maintenance activity. An important concern in the traditional fault tree reliability analysis, common-cause failures, is also considered in the component importance analysis. An example is designed and analyzed to show the selection process and to illustrate our efficient method for considering the effects of common-cause failures in the component importance analysis.
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Wang, Lihua, Zenghui Zhao, Zhongxi Tian, and Wei Sun. "Quantitative Precursory Information of Weak Shocking Failures of Composite Soft Roof." Shock and Vibration 2019 (February 17, 2019): 1–10. http://dx.doi.org/10.1155/2019/2631592.
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To reveal the mechanism of weak roof shocking in mine roadway arranged in weakly consolidated soft rock strata commonly observed in western China, a bearing system of composite roof composed of weakly consolidated soft rocks and coal layers was proposed. Then, theoretical analysis and numerical calculation were applied for instability failures of the mass bearing system with strong body and weak body. Eventually, precursory information and criteria of instability failures of the bearing system were developed. The main conclusions obtained are as follows: (1) as the elastic energy released at the postpeak failure stage of weak body contributes to system failures, the equivalent stiffness for system failures consists of the stiffness of strong body and the deterioration stiffness of weak body at softening stage; (2) during the loading process of the two-body system, isochronous sudden jumps of the deformation rate in either body can be regarded as the precursory information of weak impact failures; (3) the frequency of sudden jumps of deformation rate is significantly related to the stiffness, indicating that weak impact failures are readily observed in composite soft roof as stiffnesses of weakly consolidated soft rocks and coal seam are close to each other. This study provides references for prevention and control of weak shocking disasters of composite roofs in western China.