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Reliability Analysis
Published in Armand A. Lakner, Ronald T. Anderson, Reliability Engineering for Nuclear and Other High Technology Systems, 2017
A new tool that has appeared in the last decade which has proven to be of major aid in reliability analysis and improvement is fault tree analysis. Fault tree analysis (FTA) is a structural model for system failure modes composed of logical AND and OR symbols and failure events leading to system failure. Fault trees were initially applied to safety analysis and can be shown to be mathematically equivalent to reliability block diagrams. The main advantage of FTA is that design engineers who are unfamiliar with reliability methods find it easier to use than reliability block diagrams. This is especially important with complex system analysis since the probability of finding an engineer experienced in both system design and reliability analysis may be small.
Fault tree analysis for reinforced concrete highway bridge defect
Published in Noor Amila Wan Abdullah Zawawi, Engineering Challenges for Sustainable Future, 2016
W.S. Wan Salim, M.S. Liew, A. Shafie
In every event of failure or accident, investigations of failure causes are very significant for future improvement of the respected system of process. FT can be used to identify the combinations of event which could cause a major failure of any system. Generally, a probability of system failure may determine through a developed model of FT and evaluating each system level of failure probability, by considering an interaction at each component of the system. FT concepts can be explained as a translation of a physical system into a structured logical diagram that shows the relation between system failure and failures of the components of the system which specified causes lead to one specified main event of interest (Aven 2008, Lee et al. 1985). Fault tree analysis (FTA) is considered as a deductive approach of failure analysis starting with a potential undesirable event called TOP event. All the possible way that cause the TOP event occurred is determined using logical gates such as AND/OR gates, which are the most commonly used to combine the causal event. In general, the fault tree model consists of two basic components, ‘gates’ and ‘event’ where ‘gates’ act as connector to show the relationship between of the main ‘event’ and lower event that contribute to the occurrence of the main event (Top event). The simplified FT model can be explained through FT concept diagram as shown in Figure 1.
Probabilistic risk analysis
Published in Vicki Bier, Risk in Extreme Environments, 2018
Fault tree analysis (Barlow 1998) begins with an undesired outcome, called the “top event,” and reasons backward to identify which combinations of more basic events (e.g., component failures) could bring about the top event (e.g., failure of the system). The result is a tree that represents those sets of basic events that would be sufficient to cause the top event using “AND” and “OR” logic (and possibly more complicated logic gates as well). The tree generally goes down to the level of basic events whose probabilities can be reliably estimated from experience, judgment, and/or data. Both fault trees and event trees can be represented as logically equivalent influence diagrams and solved by well-developed influence diagram algorithms (Barlow 1998; Bobbio et al., 2001).
A Physical-organizational Method for the Functionality Assessment of A Hospital Subjected to Earthquakes
Published in Journal of Earthquake Engineering, 2022
Changhai Zhai, Peng Yu, Weiping Wen
Fault tree analysis is a versatile analytic tool for problematic system reliability and safety (Lee et al. 1985). Johnson et al. (1999) used fault trees to identify important equipment systems and components in critical facilities. Porter and Ramer (2012) developed a fault tree in collaboration with facility operators to capture a data center’s failure mechanism. Fault tree analysis begins with the statement of the undesired event (TOP event), system boundary conditions, and a description of the system operation mechanism. The logic diagram can then be constructed using AND gates, which need all lower events to occur for upper event occurrence (series arrangement) and OR gates, where the upper event will occur if any lower event occurs (parallel arrangement). It should be noted that all basic events in fault trees are assumed to be independent. If a system is complex, events can be described until the basic events are analyzable.
Defining organizational functionality for evaluation of post-disaster community resilience
Published in Sustainable and Resilient Infrastructure, 2022
S. Amin Enderami, Elaina J. Sutley, Sarah L. Hofmeyer
Fault tree analysis (FTA) is a simple analytical technique that has been widely used for quantitative reliability and safety analysis. FTA can be used for any system which is composed of discrete components with independent probabilities of failure. The fault tree (FT) itself is a qualitative and graphical model that combines a series of parallel and sequential failure events which will lead to the occurrence of a predefined undesired event in the system. This predefined undesired event is the top event of the FT. A FT applies logic gates to combine the basic events and connect them to intermediate events that lead to the top event (Ruijters & Stoelinga, 2015; Vesely et al., 1981). FTA is executed using two primary techniques: (1) qualitative vulnerability detection through a logical expression of the top event in terms of the basic events; (2) quantitative measurement of the probability of occurrence of the top event obtained through combining the failure probabilities of the basic events (Durga Rao et al., 2009).
A novel method for occupational safety risk analysis of high-altitude fall accident in architecture construction engineering
Published in Journal of Asian Architecture and Building Engineering, 2021
Among the different probabilistic risk assessment (PRA) methods, FTA is the most-widely used approach for system safety and reliability evaluation. Fault tree analysis (FTA) is a quantitative risk analysis method and can be applied to major unwanted events (Yazdi, Kabir, and Walkerb 2019). FTA method is an effective tool for the occupational safety analysis of complex system, it looks the fault status that we mostly do not want to happen as the goal of fault analysis system, then look for factors that lead to the occurrence of the fault, and looks for these next-level factors, until the original factors that we do not want to further process. In this method, the top-down analysis approach is used to find the logical relationship of the top event and all kinds of intermediate events, bottom events, etc. (embodying internal component failure, external environment changes and steeplejack error factors).