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Research On Aero-engine Reliability Assessment Based On Competing Failure

Posted on:2014-02-04Degree:MasterType:Thesis
Country:ChinaCandidate:W LiFull Text:PDF
GTID:2252330422453057Subject:Carrier Engineering
Abstract/Summary:PDF Full Text Request
Aero-engine’s reliability problems directly affect the civil aviation safety. Reliability analysis andforecasting technique is an important mean to know the aircraft engine reliability level. As a complexsystem, there’re often more failure modes within aero-engine system. The two types of failure mode,performance degradation and sudden failure, are often keeping interactive. In different stages ofsystem operation, performance forms and mechanism of action are been changing uninterruptedly, theconstantly changing is essentially a competing failure problem, increasing the complexity of thereliability analysis and prediction.This paper, from the perspective of competition failure, researches reliability assessmentproblems of aero-engine system. Combining with the physical failure mechanism in engineering, thepaper proposes reliability models based on performance degradation failure and sudden failure modesseparately, and a composite reliability analysis model based on competition failure has been putforward, with complicated data and analysis results being input variables, and verifies theeffectiveness of proposed method using some aero-engine cases. Therefore, this paper developsresearches further from the several following aspects:(1)First of all, the paper has combed research literature and methods at home and abroad basedon the degradation failure and competitive failure problem, and analyzed comprehensively therelationship among various failure modes for further study on the aero-engine failure problem.(2) The paper utilizes the method of stochastic process to describe the aero-engine degradationfailure process, and data fusion method to fuse more monitoring variables as integrated parameters.These parameters could be used as inputs of the degradation failure model of aero-engine forreliability analysis. Reliability analysis model based on the stochastic process has not only reflectedrandomness in the degradation process, but also the randomness of the parameters in monitoring. Datafusion method has avoided the problem of descriptive power deficiency using single parameter.(3) The paper used Bayes method to research aero-engine’s sudden failure process. For lack ofenough failure data due to aero-engine’s characteristic of high reliability, the paper raised anzero-failure data methods to estimate reliability based on sudden failure model, and cases forvalidating effectiveness of proposed methods.(4)On the basis of forward two parts, the paper combines degradation failure and sudden failuremodes to construct composite reliability assessment model, using the Bayesian model average method to analyze the failure of engine competition reliability evaluation problem. This method had not onlysolved the assessment accuracy problem of single failure mode, and also solved the uncertaintyproblem of various failure modes, making assessment results more accurate and scientific.
Keywords/Search Tags:competing failure, stochastic process, zero-failure data, Bayesian model averaging, reliability assessment
PDF Full Text Request
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