关键词: 多点激励;功率谱密度;Dirlik模型;弹性约束

Abstract: Aiming at the complicated exciting environment and many exciting points of the aeroengine pipeline system， the single point random vibration method can not be accurately analyzed and simulated under the boundary conditions. This paper proposes a multipoint dynamic vibration analysis method. Firstly， the dynamic vibration equation of multi-point excitation is deduced theoretically. Secondly， the dynamic response characteristics of multi-point vibration are verified by finite element simulation. According to the Dirlik model， the random vibration fatigue life of pipeline system is predicted. The dynamic characteristics and fatigue life of the structure under multi-point vibration excitation and single point vibration excitation are compared. The relationship between stress response and fatigue life of pipeline is explored according to load correlation. Finally， according to different constraint conditions， the effects of elastic constraint stiffness value on structural fatigue life are investigated. Comparative analysis found that the vibration life of pipeline system under multi-point excitation is only 22.31% of the minimum fatigue life of single point excitation. The stress response and fatigue life of pipelines change regularly with the change of phase and coherence coefficient. Moreover， with the increase of restrained stiffness， the response power spectral density of the structure increases， the amplification effect of the resonance region on the power spectral density decreases， and the fatigue life decreases. The validity of the multipoint dynamic vibration analysis method is verified.

Key words: Multi-point excitation;Power spectral density;Dirlik model;Elastic constraint