Research On Modeling And Method Of Aeroengine Turbine Shaft Fatigue Reliability

Nowadays,the air superiority becomes more and more important.As the most important part of power of aircraft,the researches of aero-engine have become the key technical fields.As the performance improvement of the aero-engine,it puts towards a high request on the stability and reliability.How to ensure the safety of aircraft under high speed,high temperature and high load is an intractable problem for researchers in various countries.The aero-engine turbine shaft is the core component of the aircraft.The main function of aero-engine turbine shaft is to associate components and transfer loads.The stable and reliable working state of the turbine shaft is the guarantee for the safe operation of the aircraft.Due to the particularity of the working condition of the aircraft,the working loads of the turbine are very complicated and random service.The main alternating loads are torque,axial force,vibration torque and bending moment.Once the fatigue failure of turbine shaft occur,it will lead to an irreversible accident.Thus,the life of the aero-engine turbine shaft will greatly affect the safety of the aircraft.The research object of this dissertation is aero-engine turbine shaft,while the research content includes the structural load analysis,the stress and strain analysis,the fatigue life prediction and the reliability analysis.The research contents can be summarized as the following aspects:(1)Analyze the logical relationship and structural relationship of the turbine shaft to determine the constraints and loads of the turbine shaft.Establish a simplified solid model of the turbine shaft and lead it into the ANSYS Workbench finite element analysis software.Based on this,the finite element model of the turbine shaft is built and the stress and strain analysis is carried out with the aid of software to determine the key to the weaker part of the turbine shaft.(2)The fatigue life prediction method and fatigue reliability analysis method commonly used in actual engineering are summarized in detail.Combined with the results of finite element analysis,the fatigue life of aero-engine turbine shaft is calculated based on the multi-axial fatigue life prediction method.Based on the results,the parameter number of dangerous parts is used to correct the calculation result.At the same time,the concept of fatigue dispersion coefficient is introduced,and the fatigue life of the whole is estimated using the small sample turbine shaft fatigue life test data.(3)Based on the Monte Carlo simulation method,the reliability analysis of the aero-engine turbine shaft is performed.Through the simulation results,the fatigue life distribution of the turbine shaft was obtained,and the histogram of the test data was drawn.The fitting test data determine the fatigue life probability distribution function and reliability function of the turbine shaft.Finally,the reliability of the turbine shaft is analyzed,and the factors that have the greatest impact on the failure probability of the turbine shaft are found.