Skip to main content

Research Repository

Advanced Search

Experimental characterisation and computational modelling of cyclic viscoplastic behaviour of turbine steel

Rae, Y.; Benaarbia, A.; Hughes, J.; Sun, Wei

Experimental characterisation and computational modelling of cyclic viscoplastic behaviour of turbine steel Thumbnail


Authors

Y. Rae

A. Benaarbia

J. Hughes

Wei Sun



Abstract

Fully reversed strain controlled low cycle fatigue and creep-fatigue interaction tests have been performed at ±0.7% strain amplitude and at three different temperatures (400°C, 500°C and 600°C) to investigate the cyclic behaviour of a FV566 martensitic turbine steel. From a material point of view, the hysteresis mechanical responses have demonstrated cyclic hardening at the running-in stage and subsequent, hysteresis cyclic softening during the rest of the material life. The relaxation and energy behaviours have shown a rapid decrease at the very beginning of loading followed by quasi-stabilisation throughout the test. A unified, temperature- and rate-dependent visco-plastic model was then developed and implemented into the Abaqus finite element (FE) code through a user defined subroutine (UMAT). The material parameters in the model were determined via an optimisation procedure based on a genetic solver. The multi-axial form of the constitutive model developed was demonstrated by analysing the thermomechanical responses of an industrial gas turbine rotor subjected to in-service conditions. A sub-modelling technique was used to optimise the FEA. A 2D global model of the rotor with a 3D sub-model of the second stage of the low pressure turbine were then analysed in turn. The complex transient stress and accumulated plastic strain fields were investigated under realistic thermo-mechanical fatigue loading (start-up and shut-down power plant loads). The sub-model was then used for local analysis leading to identification of potential crack initiation sites for the presented types of blade roots.

Citation

Rae, Y., Benaarbia, A., Hughes, J., & Sun, W. (2019). Experimental characterisation and computational modelling of cyclic viscoplastic behaviour of turbine steel. International Journal of Fatigue, 124, 581-594. https://doi.org/10.1016/j.ijfatigue.2019.01.022

Journal Article Type Article
Acceptance Date Jan 29, 2019
Online Publication Date Feb 5, 2019
Publication Date 2019-07
Deposit Date Jan 29, 2019
Publicly Available Date Feb 6, 2020
Print ISSN 0142-1123
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 124
Pages 581-594
DOI https://doi.org/10.1016/j.ijfatigue.2019.01.022
Public URL https://nottingham-repository.worktribe.com/output/1504148
Publisher URL https://www.sciencedirect.com/science/article/pii/S0142112319300313

Files




Downloadable Citations