APPLICATION OF FUZZY LOGIC TO THE MUHLBAUER MODEL FOR PIPELINE RISK ANALYSIS / APLICAÇÃO DA LÓGICA NEBULOSA AO MODELO MUHLBAUER PARA ANÁLISE DE RISCO EM DUTOS

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

W. Kent Muhlbauer made a detailed identification of approximately 300 different conditions that influence in the evaluation of the Risk in a pipeline, so, He proposed a punctuation system that is known as the method of Muhlbauer. Muhlbauer`s method evaluates the several variables that influence in the pipeline Risk by the attribution of quantitative values. However, being a qualitative method, these variables cannot be informed through exact values. These variables can be treated as coming of distributions random. However, to identify the distributions random can demand a lot of effort. Being like this, instead of assuming that the evaluations of the variables have distributions random, it can be considered that they have distributions given by fuzzy sets and numbers. In the present work, the values numeric presents in the model Muhlbauer will be admitted as no deterministic, admitting an uncertainty. This uncertainty depends on the engineer specialist knowledge about the Risk. To incorporate this uncertainty in the calculation of the value of the Risk Muhlbauer tried to work with the fuzzy sets and numbers. In the analysis of the uncertainties by the fuzzy sets, it is necessary to define the linguistic variables (VL), the linguistic values of input and output of VL, the membership functions, besides the fuzzy rules. With these, a System of Logic Fuzzy (SLF) is implemented based on Mamdani`s inference. In the case of the fuzzy numbers, they admit a more probable value and an uncertainty. This uncertainty is evaluated by a function of normalized membership. Sum, subtraction, multiplication and division operations are possible for the numbers fuzzy. As result, it is possible to find not only a number that defines the Risk as also the uncertainty (range of values) that the Risk can have. It is a function of the uncertainties of the individual evaluations of the variables. The present work proposes a basic model of Management of Risk (GR) and Analysis of Structural Integrity (AIE) for pipeline with damage corrosion. For that, the results of an AIE VIII level one applied to the pipeline are associated with the results of Muhlbauer`s method through a Risk Matrix. Starting from an AIE level one, the calculation of the Residual Life (T *) is evaluated. T * is compared with a ideal life (VD), which is obtained of the Risk Matrix. If T * is smaller than VD, it is recommended to do an AIE level II. If T * is larger than VD is determined a Time of Inspection based on the reliability analysis.

ASSUNTO(S)

risk analysis dutos analise de risco modelo muhlbauer pipes muhlbauer s model

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