Probabilistic integrity assessment of turbine disks in presence of potential defects

Abstract

Rotor disks for gas turbines are heavy components and are usually designed following a safe-life approach, where the low-cycle fatigue analysis is carried out referring to design life curves with suitable probabilistic margins. However, in the case of such a heavy component there is the possibility of rare occurrence of undetected defects or, better, the need to identify the defect acceptability for the different rotor regions (considering stress, temperature, mission profile). In order to carry out such calculations for a turbine rotor disk a software named {AStrID} (Assessment of the Structural Integrity of Disks) has been developed in close cooperation between Politecnico di Milano and Ansaldo Energia (AEN). This paper summarizes its background and some of the relevant features.