Stress calculations for lifetime prediction in turbine blades

Abstract

In order to predict fatigue lifetime in cooled turbine blades it is necessary to know stabilized cyclic stress and strain fields for typical ground-to-ground cycle.Previous works permit to obtain the viscoplastic temperature dependent behavior and the classical one-dimensional plane cross-section method gives the stress and strain fields on the blade.However this classical method does not take into account the restraining effects of moments due to action of centrifugal forces on the deflected blade. This paper presents an extension of the plane cross-section method in which the coupled problem induced by these restraining effects is solved without iteration. p]Results are given for a turbine blade made of a refractory alloy and compared with the case in which restraining effects are neglected.