| Turbine blades are widely used in various gas-powered equipment such as engines.Among them are aero-engines,and their role in aero-engine components is particularly special.It can be said that the main engine of aero-engines is the main heart.It is the power participant of the aero-engine,which is the decisive factor for the dynamic performance and reliability of the aircraft.Although the turbine blade components are currently highly reliable due to strict standards and practices,the turbine blades in the normal working environment The failure is still a common situation that jeopardizes flight safety.As one of the key components of aero-engine fracture,turbine blades have long-term working under abnormal conditions.Due to the combination of various complex loads,the probability of failure is greatly increased.Fatigue fracture is found in the failure analysis of faulty parts of turbine blades.The failure has the highest proportion of total failures and is its most important failure mode.Therefore,it is necessary to use scientific means to correctly analyze and evaluate the reliability of aero-engine turbine blades and maximize their effects on the premise of avoiding accidents.In this paper,aeronautical low-pressure turbine blade is taken as the research object,and the reliability analysis of the main failure mode of the turbine blade is carried out.The main research work is as follows:The physical analysis of turbine blade failure is carried out,and the stress of turbine blade under maximum operating conditions is calculated by finite element software ANSYS Workbench.Based on the results of finite element analysis,the maximum stress sample data of turbine blade under low cycle fatigue fracture failure mode are obtained by combining finite element numerical simulation,response surface method and Monte Carlo method.The process of material strength degradation is studied.The dynamic reliability of turbine blades under low cycle fatigue fracture failure mode is solved by stress-strength interference model.Turbine blade is the "backbone" of aero-engine when it is used in various gas-powered equipment such as engine.It plays a decisive role in the dynamic performance and reliability of aircraft.As one of the key components of aero-engine fracture,turbine blades work in abnormal conditions for a long time,and are subject to a variety of complex loads,so the probability of failure is greatly increased.In the failure analysis of turbine blades,it is found that the fatigue fracture failure accounts for the highest proportion of the total failure and is the main failure mode.Therefore,it is necessary to adopt scientific means to correctly analyze and evaluate the reliability of aeroengine turbine blades,and to maximize their role in the premise of avoiding accident disasters.In this paper,the main failure modes of an aeronautical lowpressure turbine blade are analyzed.The main research work is as follows:(1)Physical analysis of turbine blade failure is carried out.The stress of turbine blade under maximum operating conditions is calculated by finite element software ANSYS Workbench.Based on the results of finite element analysis,the maximum stress sample data of turbine blade under low cycle fatigue fracture failure mode are obtained by finite element numerical simulation,response surface method and Monte Carlo method.The dynamic reliability of turbine blades under low cycle fatigue fracture failure mode is solved by the degree of interference model.(2)Based on the low-cycle fatigue life model of turbine blade,considering the randomness of the correlation coefficient in the life model,Monte Carlo sampling is used to analyze the life sample data and the reliability model of low-cycle fatigue life of turbine blade is established by using the method of probability weighted moment parameter estimation.(3)The low-cycle composite fatigue failure mode of turbine blade is studied,and the maximum stress of turbine blade under composite failure mode is analyzed.Based on the established structural strength degradation model and stress-strength interference model,the dynamic reliability of turbine blade under composite failure mode is solved.(4)The modal analysis of turbine blade is carried out,and the vibration characteristics of turbine blade are analyzed.The modal characteristics of turbine blade,the relationship between dynamic frequency and static frequency,and the sensitivity of anti-resonance response sample data are obtained,which can provide reference for avoiding resonance and frequency modulation modification of turbine blade. |
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