A lifing method based on R5 and viscoplasticity modelling and its application to turbine rotor under thermomechanical loading

Bonetti, Rossella; Hadjipakkos, P.; Rae, Yarik; Hughes, Jeremy; Sun, W.

Abstract

An integrated life assessment procedure for structures operating under thermomechanical loading has been
developed. The methodology uses a viscoplasticity based framework combined with the R5 life assessment code. The
viscoplastic constitutive model used for the stress-strain analysis is derived from the Chaboche-Lemaitre formulation
that allows to directly obtain the required parameters for the R5 assessment as stress relaxation per cycle and the
elastic follow-up factor. The R5 procedure is therefore significantly simplified. The proposed life assessment procedure
is demonstrated on a martensitic steel (FV566) industrial gas turbine rotor under a typical start up – shut down
operation. The effect of creep-fatigue interaction at different locations within the rotor structure is assessed and the
remaining life at each location is calculated. A sensitivity study is performed at half load, which shows an increase in
lifetime of the rotor.

Citation

Bonetti, R., Hadjipakkos, P., Rae, Y., Hughes, J., & Sun, W. (2020). A lifing method based on R5 and viscoplasticity modelling and its application to turbine rotor under thermomechanical loading. Engineering Failure Analysis, 110, Article 104416. https://doi.org/10.1016/j.engfailanal.2020.104416

• Journal Article Type: Article
• Acceptance Date: Jan 27, 2020
• Online Publication Date: Jan 28, 2020
• Publication Date: 2020-03
• Deposit Date: Jan 28, 2020
• Publicly Available Date: Jan 29, 2021
• Journal: Engineering Failure Analysis
• Print ISSN: 1350-6307
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 110
• Article Number: 104416
• DOI: https://doi.org/10.1016/j.engfailanal.2020.104416
• Keywords: General Engineering; General Materials Science
• Public URL: https://nottingham-repository.worktribe.com/output/3821350
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S1350630719313925
• Additional Information: This article is maintained by: Elsevier; Article Title: A lifing method based on R5 and viscoplasticity modelling and its application to turbine rotor under thermomechanical loading; Journal Title: Engineering Failure Analysis; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.engfailanal.2020.104416; Content Type: article; Copyright: © 2020 Elsevier Ltd. All rights reserved.