Strength Analysis And Life Span Of A Aero-engine Turbine Disk And Blades

The turbine disc and blade which are the key component of engine tubine rotor system work under abominable condiation of high cyclic temperature and mechanical load. In order to ensure the stability and reliability of the airplane when it is in service, an accurate analysis of the strength and the fatigue life for the turbine disc and blade are needed imminently. This paper studies a satisfying result of the strength and life predication under the background of needing to prolong a civil aviation turbine life.Firstly, this paper summarizes the disposal of the flight mission profile, and focuses on nineteen actual flight cyclic load data, the rain-flow count loading cycles and loading duration of the rotate speed and exhaust temperature etc. is obtained by statistical calculation and the damage of the partial loading cycles is analyzed. Based on the analysis above, we wipe off the invalid load data which do no harm on the fatigue damage, and an actual cyclic load spectrum is obtained. This load spectrum which is the groundwork for the strength and life of the turbine rotor system provides the basis of formulating accelerated mission test spectrum.Secondly, ANSYS software is employed to construct a three-dimensional finite element modal of turbine disc and blade. Circumstances of the contact nonlinear between tubine disc mortise and blade tenon, the elastic-plasticity deformation of material and the thermal stress caused by non-uniform temperature are considered, and a three dimension nonlinear cyclic stress-strain analysis is conducted. Then, the dangerous point caused by fatigue rupture is found, the stress profile is established. Further more, the static strength of the turbine disc and blade is studied by using EGD-3 rule.Finally, depend on the stress-strain analysis results and the material's fatigue characteristics, we select S-N curve method and Manson-coffin formula respectively for the fatigue damage calculation and life prediction of the turbine disc. By using two different life calculation methods which are mentioned above, the same result is derived to demonstrate the validity and efficiency of the method and calculation process. We find the turbine blade is on the complicated stress status, so four different rules for achieving equivalent stress are used to contrast. Then the fatigue life of the tubine blade is achieved by using Larson-Miller formula.Through the analysis of stress and life above, this paper provides a reference to improving the reliability and prolonging the fatigue life of the tubine.