Abstract

Mechanical vibrations in turbine stages are one of the most significant reasons for a failure of bladed discs assemblies in turbines and compressors. A numerical example of a transient analysis during a run-up and a run-down process and the estimated fatigue life of the tuned and the mistuned bladed discs are presented. Life estimates are made using the linear and nonlinear cumulative damage theories and a comparison of the results is presented. It is done in order to show the importance of the consideration of the detuned system and the differences between the tuned bladed disc analysis.

The blade is modelled on a basis of extended beam theory including a bending-bending-torsional vibration. The disc is modelled by the moderately thick plate theory. The equation of motion is obtained by using the extended Hamiltons principle and the Ritz method,