Abstract: Taking performance indexes as reliability criterion for systems with performance degradation has practical engineering significance. A performance reliability analysis method based on component regressive mechanism and performance degradation process is presented, which integrates the advantages of path tracing methods and graphical methods. The response surface of the piston pump flow rate is created, and the parameters of the variables and their regressive path are analyzed simultaneously. The degradation path of the component parameter has some randomness caused by the uncertainties of the internal and external factors, this causes the degradation of flow, which is taken as reliability criterion for piston pump performance, also to have randomness. Based on the performance reliability criterion of piston pump and the set theory, the analytical method for the performance reliability of piston pump is given. The cumulative distribution function (CDF) curve of piston pump performance reliability is obtained on the basis of a high-efficiency Monte-Carlo simulation method. The developed method consider the random influence of internal and external uncertainties, it can overcome the disadvantage of the traditional reliability analysis method, and can be popularized and applied in other complex systems with performance degradation.

Key words: Degradation, Mechanism, Performance reliability, Piston pump, Process