Abstract

This paper analyzes the possibility of resonances within a control stage of a high speed turbine. An original method for steady state operation is used for the analysis of the stiffness matrix representing: initial displacement blade (nominal shape blade obtained by nominal working point of turbine) and residual stresses following local crossing yield plastic strain. In theanalysis there has been found a possibility of occurance of the resonance frequency, and mistuningby showing the safe working ranges. The calculation used the 3D modal and harmonicanalysis within computational solid dynamics (CSD) and the results were compared with the0D data from literature. After local crossing of yields stresses, on the basis of the harmonicanalysis, there has been shown operation of the blade in the resonance point. Before crossingthe yield stresses the blade is working in mistuning and a safe point.