飞机液压泵二维性能退化的可靠性评估

An Aircraft hydraulic pump provides high-pressure energy for aircraft manipulation, landing gear retraction and braking. Maintaining its reliability and safety is critical. In this paper, we construct a mixed lubrication wear degradation model based on the micro topography for rotor-valve plate friction pairs and axial pump mechanical seals. The unified stochastic process model is used to describe the degradation process of these two degradation performance indicators, Copula functions are used to describe the dependent relationships between two performance indicators. Bayesian Markov chain Monte Carlo method is used to estimate unknown parameters in the degradation model considering two dependent performance indicators. The results of the estimation are then utilized to conduct reliability evaluations for aircraft hydraulic pumps. The proposed theory and method were verified through real degradation test data of return oil flow for hydraulic pumps and friction torque for mechanical seals. The results show that the degradation model considering two dependent performance indicators can increase the accuracy of reliability estimation and lifetime prediction.