Risk Assessment of Water Treatment Plants Using Fuzzy Fault Tree Analysis and Monte Carlo Simulation

Abstract Conventional Fault Tree Analysis (FTA) suffers from a variety of shortcomings which must be considered in critical analysis. The main disadvantage of FTA is its inability to model the dynamic failure behaviors of the components. Accordingly, Dynamic Fault Tree Analysis (DFTA) has been proposed to overcome such limitation. In this study, first, Monte Carlo simulation (MSC) approach is used to handle internal calculations of dynamic gates. The second main weakness of common FTA is about handling the different types of uncertainties. Hence, in the second step of this study, a combined of fuzzy numbers and MCS has been proposed to overcome the limitation of FTA in dealing with uncertainties. The main purpose of this paper is a comparative study on differences between MCS and Fuzzy-Monte Carlo simulation (FMCS) approaches for solving DFTA of a typical mechanical system. From available literatures, our proposed approaches have been demonstrated on different renewable energy systems, as case studies, and results are discussed. A comparison between MCS and FMCS shows that the results of FMCS method are reasonable and more realistic. Finally, in the last section, conclusions and some of the future wok are proposed.

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FPGA-based Monte Carlo simulation for fault tree analysis

Microelectronics Reliability ◽

10.1016/j.microrel.2004.01.016 ◽

2004 ◽

Vol 44 (6) ◽

pp. 1017-1028 ◽

Cited By ~ 48

Author(s):

Alireza Ejlali ◽

Seyed Ghassem Miremadi

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Fault Tree ◽

Fault Tree Analysis ◽

Tree Analysis

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FAULT TREE ANALYSIS OF FLY-OUTS IN METAL LATHE MACHINE OPERATIONS

10.7562/se2015.5.01.02 ◽

2015 ◽

Vol 5 (1) ◽

Author(s):

AKINYEMI OLASUNKANMI ORIOLA ◽

GIWA SOLOMON OLANREWAJU ◽

ADEYEMI HEZEKIAH OLUWOLE ◽

AKINTAN ADESHINAAYOMI LAWAL ◽

MEBUDE OLADAPO

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Boolean Algebra ◽

Fault Tree ◽

Fault Tree Analysis ◽

Tree Analysis ◽

Before And After ◽

Safety Interventions ◽

Lathe Machine ◽

Safety Intervention

The most probable accident in lathe machining has been identified to be fly-outs. This study aim at determining the causal factors leading to fly-out accidents during lathe machining operations and subsequently determine the probability of occurrence of fly-out accident. Fault tree analysis (FTA) was used to identify risk factors. Boolean algebra equations were used to analyse the probability of fault occurrence. Monte Carlo simulation was carried out using OpenFTA software and the output of 1000 iterations was compared with the output of Boolean algebra. Safety intervention alternatives were evaluated by comparative analysis of before and after implementation of safety measures. Twenty four (24) minimum cut sets comprising of 21 basic events and 3 undeveloped events were identified. The top event has probability of 0.748 signifying high likelihood for fly-out. Monte Carlo simulation gave lower and upper bounds probabilities of 0.725 and 0.773, respectively. The event of the chuck key not pulled out of the chuck before machining begins was however noted to have the highest contribution to the occurrence of fly-out accident. The result of safety intervention alternatives revealed that the probability of fly-out becomes 0.192 with a safety benefit of N27, 800 after the first tier implementation. Other tiers of safety interventions will see the probability of fly-out go further down. By this, safety engineer has a scale for effectiveness of respective safety intervention programmes. Key words: fly-out, accident, safety, intervention, lathe, machine, operation

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