Identification of inelastic material parameters for modified 9Cr–1Mo steel applicable to the plastic and viscoplastic constitutive equations

Koo, Gyeong-Hoi; Kwon, Ji-Hyun

doi:10.1016/j.ijpvp.2010.11.004

Cited by 26 publications

(26 citation statements)

References 10 publications

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“…Although quite a few constitutive LCF models exist for martensitic/ferritic steels in general (Aktaa and Petersen, 2011;Aktaa and Schmitt, 2006;Hatem and Zikry, 2009) and grade P91 steels in particular (Koo and Kwon, 2011;Koo and Lee, 2007;Saad et al, 2011;Taguchi et al, 1990;Yaguchi and Takahashi, 2000), only a small number of them have both the evolution of dislocation densities and their interactions as the fundamental basis of their formulation (Fournier et al, 2011;Fournier et al, 2005;Sauzay et al, 2008;Sauzay et al, 2005). The last set of cited modeling efforts are however based on relatively different assumptions and their robustness mostly depends on the careful selection of model parameters that are accordingly modified depending on the nature of loading.…”

Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Dislocation-based constitutive modeling of martensitic/ferritic steels at elevated temperatures. Part II: Cyclic behavior without hold time effects

Kalyanasundaram

Saxena

Holdsworth

2013

International Journal of Plasticity

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Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Dislocation-based constitutive modeling of martensitic/ferritic steels at elevated temperatures. Part II: Cyclic behavior without hold time effects

Kalyanasundaram

Saxena

Holdsworth

2013

International Journal of Plasticity

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“…The model was modified by Barrett et al [2] for multiaxial TMF problems which are independent of applied strain rate using a hyperbolic sine viscoplastic model. Multiaxial Chaboche model has also been used by Koo and Kwon [3] and Zhang et al [18] for cyclic plasticity modelling of martensitic steels. Bernhart et al [19] implemented isotropic hardening strain memory effect within multiaxial Chaboche model for forging tool steel.…”

Section: Introductionmentioning

confidence: 99%

“…The physically relevant material parameters are determined and optimised using experimental results. Although many material parameter identification procedures can be found in the literature [1][2][3][4][5][6], there are uncertainties in determining the limits for the parameters used in the optimisation procedure. This could result in unrealistic parameters while optimising using experimental data.…”

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confidence: 99%

Determination of material parameters for a unified viscoplasticity-damage model for a P91 power plant steel

Kyaw

Rouse

et al. 2016

International Journal of Mechanical Sciences

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The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractSocietal pressures are mounting on electricity operators to operate traditional fossil-fuel power plants in an efficient and flexible manner in conjunction with renewable power plants. This requires the uses of high frequency start up -shut down load profiles in order to better match market demands. As such, high temperature/pressure components such as steam pipe sections and headers experience fluctuating mechanical and thermal loads. There is therefore an industrial need for the accurate prediction of fatigue and creep damage in order to estimate remnant component life. In the present work, a continuum damage model has been coupled with a Chaboche unified viscoplastic constitutive model in order to predict stress-strain behaviour of a P91 martensitic steel (a material used for power plant steam pipes) due to cyclic plasticity and damage accumulation. The experimental data used here are from the previous work [1]. Cyclic fully reversed strain controlled experiments (±0.4%, ±0.25% and ±0.2% strain ranges) and cyclic test with a dwell period (±0.5% strain ranges) for a P91 martensitic steel under isothermal conditions (600°C) are utilised. The physically relevant material parameters are determined and optimised using experimental results. Although many material parameter identification procedures can be found in the literature [1][2][3][4][5][6], there are uncertainties in determining the limits for the parameters used in the optimisation procedure. This could result in unrealistic parameters while optimising using experimental data. The issue is addressed here by using additional dwell test to identify the limits for stress relaxation parameters before using Cottrell's stress partition method to identify the limits for strain hardening parameters. Accumulated stored energy for damage initiation criterion and damage evolution parameters are also extracted from the experimental results. The estimated failure lifetimes for ±0.4%, ±0.25% and ±0.2% cases are 1600, 4250 and 9500 cycles, respectively, as opposed to 1424, 3522 and 10512 cycles as given by experiments.

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“…P91 steel is a 9Cr martensitic steel typically used for plant header and piping systems due to its high creep strength [3]. A number of material models capable of simulating the constitutive behaviour of candidate materials already exist, including the unified Chaboche model [4][5][6][7] and the twolayer viscoplasticity model [8,9]. However, a hyperbolic sine material model has been chosen as it is more representative of the key mechanisms of deformation [10], enabling strain-rate independence of the material parameters and offers greater accuracy through the full stress regime [1,2,11].…”

Section: Introductionmentioning

confidence: 99%

Multiaxial cyclic viscoplasticity model for high temperature fatigue of P91 steel

Barrett

Farragher

O’Dowd

et al. 2014

Materials Science and Technology

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This paper presents a novel multiaxial, cyclic viscoplasticity material model for high temperature low cycle fatigue of P91 power plant steel. The model incorporates mechanisms-based variable strain-rate sensitivity and the key high temperature cyclic deformation phenomena of cyclic softening and non-linear kinematic hardening. The model has been calibrated to accurately represent the cyclic high temperature constitutive behaviour of ‘as received’ P91 steel. Details on the material Jacobian, with the consistent tangent stiffness for finite element implementation, are presented. The multiaxial implementation is applied to a notched specimen under strain-controlled loading at 600°C and a thin walled pipe under representative pressurised thermomechanical fatigue loading conditions. It is shown that the model for variable strain-rate sensitivity of the present paper predicts significantly different Coffin–Manson notch fatigue life compared to the Chaboche power law model. Ratchetting is shown to be a key candidate failure mechanism for next generation thermomechanical power plant loading conditions, for thin walled pressurised pipes.

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Identification of inelastic material parameters for modified 9Cr–1Mo steel applicable to the plastic and viscoplastic constitutive equations

Cited by 26 publications

References 10 publications

WITHDRAWN: Dislocation-based constitutive modeling of martensitic/ferritic steels at elevated temperatures. Part II: Cyclic behavior without hold time effects

WITHDRAWN: Dislocation-based constitutive modeling of martensitic/ferritic steels at elevated temperatures. Part II: Cyclic behavior without hold time effects

Determination of material parameters for a unified viscoplasticity-damage model for a P91 power plant steel

Multiaxial cyclic viscoplasticity model for high temperature fatigue of P91 steel

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