Author : Harinath SP, Sharath Chandra GV, Shreyas PM and Kumar K Gowda

Aero engine rotor burst evaluation is one of the most important problems to be taken care off, whenever it comes to designing a turbo machinery disc. The consequences of a failure can be intense, since the disc fragments into multiple pieces and they are hurled away in all the possible direction at high speeds. Due to high thermo-mechanical loading conditions the disc is subjected to varying degrees of temperature from bore to rim. However, the centrifugal force dominates in the disc which ranges from 80%-90% and the rest can be treated as thermal and gas loads. The challenge lies at designing a disc for off-design conditions with their varying loads and duty cycles. In present work evaluation of safety limits and low-cycle fatigue (LCF) life estimation of an aero engine disc through classical methods and blending the terminologies with simulation engineering to arrive at a probable interpretation of number of duty cycles is carried out. The methodology compares the fatigue parameters involved in evaluation of disc life at off-design condition through sensitivity analysis. The design tool closely connects the flight certification FAA and EASA the regulating agencies for safety in air transportation vehicles. The off-design speed regulations through API and MIL handbook for material specification are considered to carry out design of experiments using finite element analysis approach

Keywords: Engine rotor burst, Duty cycles of turbo fan, over-speed and burst margins, low cycle fatigue, Robinson’s and Hallinan’s failure criteria’s, FAA, EASA, Universal slope and Coffin-Manson method.

Article published in International Journal of Current Engineering and Technology, Vol.8, No.2 (March/April 2018)