1. An improved unified viscoplastic model for strain-rate sensitivity in high temperature fatigue
- Author
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Barrett, Richard A., O'Donoghue, P. E., Leen, Sean B., and ~|1267883|~
- Subjects
Cyclic viscoplasticity ,P91 steel ,Thermo-mechanical fatigue ,sinh constitutive model ,Strain-rate sensitivity - Abstract
Journal article An improved unified cyclic viscoplastic material model for high temperature fatigue of P91 steel is presented. The primary enhancement over existing models is in relation to strain-rate independence of parameters, for accurate interpolation and extrapolation across a range of strain-rates and stress regimes, as relevant to flexible operation of high temperature power generation plant. The model combines a hyperbolic sine constitutive equation with anisothermal cyclic evolution of isotropic and kinematic hardening variables. The material model is developed from a thermodynamic framework and is implemented in multi-axial form within a user material subroutine. The user material subroutine is calibrated and validated for P91 steel across a range of cyclic (isothermal fatigue and thermo-mechanical fatigue) and non-cyclic high temperature loading conditions. A novel method for the identification of the cyclic viscoplastic material parameters is also presented. Science Foundation Ireland SFI/10/IN.1/I3015 peer-reviewed
- Published
- 2013