Design of load spectrum for hydraulic pumps based on extreme value theory

Hydraulic pumps with high reliability are important for airplanes, so the load spectrum of it in life tests should be designed approximate to real working conditions. And a way to design load spectrum without former experimental data is urgently needed. This paper focuses on designing the load spectrum for aircraft hydraulic pumps. Combing flight mission with flight profile to make flow rate demand analysis to obtain load cycle and basic load spectrum for tests. Based on extreme value theory, including Peaks Over Threshold (POT) analysis and General Pareto Distribution (GPD) Model, this paper presents a method of load spectrum extrapolation to reduce the influence of uncertainty in extreme situations. The original designed load spectrum is compared with the extrapolated load spectrum, and the latter shows a good fitting with original spectrum and a higher degree accuracy to real working conditions.