Research On Shock Response And Life Prediction Method Of Engine Accessory Drive System

Due to the transient change of engine working condition,the accessory drive system will be frequently impacted by the impact load,which is easy to cause the transmission shaft fatigue failure and other malignant accidents.Therefore,it is of great value to study the dynamic response characteristics and fatigue life prediction of engine accessory drive system under impact load for improving the stability and safety of engine operation.In order to solve the problem of fracture of accessory drive system of aeroengine under random fatigue load,combined with the structural characteristics of accessory drive system of aeroengine,a typical dynamic model of three parallel shaft gear drive system in accessory drive system of aeroengine is established,and analyzes the time-varying meshing stiffness of the gear.Based on Newmark algorithm,the dynamic response of engine accessory drive system under impact load is calculated and analyzed.The results show that the load end of the sub structure of the aero-engine accessory drive system is more affected than the power input end under the impact load,and the vibration amplitude of the system becomes larger after the impact,but the vibration frequency remains unchanged.A fatigue life prediction method based on grey estimation and polynomial variation theory is proposed.Based on the grey model and polynomial variation theory,two-dimensional load spectrum and equal amplitude fatigue median surface are obtained.Taking parallel shaft-gear transmission structure as an example,the fatigue life prediction of the structure is carried out based on miner fatigue cumulative damage theory and verified by experiments.The results show that the calculated value of fatigue median life is slightly less than the test value,which proves that the calculation method in this paper is reliable and conservative,and provides theoretical reference and data basis for improving the fatigue life of accessory drive system.