An introduction to fault tree analysis with emphasis on failure rate evaluation

1975 ◽  
Vol 14 (2) ◽  
pp. 105-119 ◽  
Author(s):  
G.W.E. Nieuwhof
2013 ◽  
Vol 378 ◽  
pp. 403-407
Author(s):  
Jian Feng Yang ◽  
Ling Ling Chen ◽  
Wen Bin Liu

Flue gas turbine is one of the highest failure rate of the power equipment in oil refinery now.It is a key role to achieve saving energy and reducing consumption, the goal ofpollution reduction and the safe, reliable and efficient operation of the flue turbine in refinery. Therefore, it is of great significance to the fault diagnosis of the blade by summarizing the fault reason of the flue gas turbine and using fault tree analysis.


Author(s):  
Tong Wang ◽  
Xi Chen ◽  
Zhikai Cai ◽  
Junnan Mi ◽  
Xiaomin Lian

In order to ensure safety and reliability, some safety-related electrical and electronic (E/E) systems in vehicles need to be designed as a whole-redundancy system. Although ISO 26262 provides guidance for the analysis of random hardware failure, the problem of estimating whether the safety-related E/E systems, especially whole-redundancy system can meet the index of the ASIL level in ISO 26262 is still unsolved. Fault tree analysis (FTA) is one of the basic methods to analyze random hardware failure of a vehicle’s E/E systems quantitatively. In generic FTA, the quantitative analysis of dynamic logic gates, which usually exist in the fault tree of whole-redundancy system, cannot be calculated. Meanwhile, Markov chain can solve the problem of quantitative calculation of dynamic fault tree, but brings a side-effect of complicating the calculation of static logic gates in fault trees. In order to evaluate random hardware failure of a vehicle E/E system more concisely and effectively, and to estimate if a new safety-related E/E system’s random hardware failure rate can meet the index demand in ISO 26262, this study proposed a mixed model based on FTA and Markov chain. First, the definition of random hardware failure and fault classification were clarified. Then, a mixed model based on FTA and Markov chain was proposed. Finally, a whole-dual-redundancy steer by wire system was used as an example to test the validity of the mixed model. This study not only proposed a new mixed model based on FTA and Markov chain for the calculation of a whole-redundancy system’s random hardware failure rate, but also provided a new quantitative validation method for safety-related E/E systems in vehicles that need to meet the reliability index requirement in ISO 26262.


2020 ◽  
Vol 11 (1) ◽  
pp. 134
Author(s):  
Darja Gabriska

In an automated systems environment is very important to predicted failures or unexpected situations to achieve system reliability. Failure of such systems can cause serious property damage, the environment, damage to human health or cause death. The essential task is to determine the tolerable and acceptable risk. The required level of risk for safety-critical systems can be achieved by using international technical standards and applying safety functions. Safety functions are implemented using an electrical/electronic/programmable electronics (E/E/PE) safety-related system. Technical standards offer the aspect of balancing risk tolerability according to the relevant, reliable safety functions. Based on the specific architecture of the whole system, it is possible to determine the maximum failure rate of the probability of failure on demand (PFDSYS) of the selected architecture. Subsequent application of reliability analysis using the event tree analysis (ETA) and fault tree analysis (FTA) methods can optimize the failure rate of the entire system. Application of reliability analysis using event tree analysis (ETA) and fault tree analysis (FTA) methods can only theoretically optimize the failure rate of the entire system with constant initial conditions and constant parameters of the reliability functions. The article proposes a new methodology for dynamic analysis of the state of system reliability as a function of the system operation time, maintenance frequency and system architecture. As a result of the methodology is a library of standard element architectures and simulation models which allows predicting and optimizing the reliability of E/E/PE safety-related systems.


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