Study of creep–fatigue behavior in a 1000 MW rotor using a unified viscoplastic constitutive model with damage

Wz, Wang; Buhl, Patrick M.; Klenk, Andreas; Yz, Liu

doi:10.1177/1056789515576766

Cited by 26 publications

(10 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, in these works, the contribution of plasticity to the overall failure mechanism is considered negligible compared to creep. In a similar way, a large number of works have been done to estimate the creep-fatigue life of components using numerical methods based on complex constitutive models [6,[14][15][16] or by approximated methods [17][18][19][20]. However, for all the cases introduced the loading conditions have been well below certain levels, and not even close to the plastic limit of the structure.…”

Section: Introductionmentioning

confidence: 99%

On the Plastic Strain Accumulation in Notched Bars During High-Temperature Creep Dwell

Barbera

Chen

2020

J. mech.

View full text Add to dashboard Cite

Structural integrity plays an important role in any industrial activity, due to its capability of assessing complex systems against sudden and unpredicted failures. The work here presented investigates an unexpected new mechanism occurring in structures subjected to monotonic and cyclic loading at high temperature creep condition. An unexpected accumulation of plastic strain is observed to occur, within the high-temperature creep dwell. This phenomenon has been observed during several full inelastic finite element analyses. In order to understand which parameters make possible such behaviour, an extensive numerical study has been undertaken on two different notched bars. The notched bar has been selected due to its capability of representing a multiaxial stress state, which is a practical situation in real components. Two numerical examples consisting of an axisymmetric v-notch bar and a semi-circular notched bar are considered, in order to investigate different notches severity. Two material models have been considered for the plastic response, which is modelled by both Elastic-Perfectly Plastic and Armstrong-Frederick kinematic hardening material models. The high-temperature creep behaviour is introduced using the time hardening law. To study the problem several results are presented, as the effect of the material model on the plastic strain accumulation, the effect of the notch severity and the mesh element type and sensitivity. All the findings further confirm that the phenomenon observed is not an artefact but a real mechanism, which needs to be considered when assessing off-design condition. Moreover, it might be extremely dangerous if the cyclic loading condition occurs at such a high loading level.

show abstract

Section: Introductionmentioning

confidence: 99%

On the Plastic Strain Accumulation in Notched Bars During High-Temperature Creep Dwell

Barbera

Chen

2020

J. mech.

View full text Add to dashboard Cite

show abstract

“…Many structural components at elevated temperature are usually subjected to thermo-mechanical fatigue (TMF) loading in service (Wang and Liu, 2019;Zhu et al, 2018). During TMF loading, the fatigue, oxidation, and creep damages can be induced; and the relative contributions of these damages will vary with the different materials and loading conditions (Gosar and Nagode, 2015;Guth et al, 2015;Jones et al, 2017;Liu and Pons, 2018;Pandey et al, 2019;Roy et al, 2015;Shah et al, 2015;Wang et al, 2016). Moreover, the damage behavior is more complex under axialtorsional thermo-mechanical fatigue (AT-TMF) loading.…”

Section: Introductionmentioning

confidence: 99%

Fatigue–oxidation–creep damage model under axial-torsional thermo-mechanical loading

Shang

Cui

et al. 2019

International Journal of Damage Mechanics

View full text Add to dashboard Cite

A fatigue–oxidation–creep damage model that can take into account the effect of multiaxial cyclic feature on the damage mechanism is proposed under axial-torsional thermo-mechanical fatigue loading. In the proposed model, the effects of non-proportional additional hardening on fatigue, oxidation, and creep damages are considered, and the variation of oxidation damage under different high temperature loading conditions is also described. Moreover, the intergranular creep damage needs to be equivalent to the transgranular damage before accumulating with the fatigue and oxidation damages. The fatigue, oxidation, and creep damages can be expressed as the fractions of fatigue life, critical crack length, and creep rupture time, respectively, which allows the linear accumulation of different types of damages on the basis of life fraction rule. In addition, the proposed model is validated by various fatigue experimental results, including uniaxial thermo-mechanical fatigue, axial-torsional thermo-mechanical fatigue, and isothermal axial-torsional fatigue under proportional and non-proportional loadings. The results showed that the errors are within a factor of 2.

show abstract

“…The continual improvement in understanding of underlying microstructure variables in 9% Cr steels has led to the development of new constitutive models or modification in existing models. Applicability of constitutive relationships associated with the single or multiple state variables towards the description of creep behaviour of tempered martensitic steels can be found elsewhere (Biglari and Nikbin, 2017;Christopher and Choudhary, 2018;Christopher et al, 2012;Dyson and McLean, 1998;Eisentra¨ger et al, 2017;Hore and Ghosh, 2011;Liu and Pons, 2018;McLean and Dyson, 2000;Murchu´et al, 2017;Naumenko et al, 2011aNaumenko et al, , 2011bOruganti et al, 2011;Semba et al, 2008;Wang et al, 2016;Yin and Faulkner, 2006). Most of the creep models were based on the works of Dyson and McLean (1998) and McLean and Dyson (2000).…”

Section: Introductionmentioning

confidence: 99%

Prediction of long-term creep behaviour of Grade 91 steel at 873 K in the framework of microstructure-based creep damage mechanics approach

Christopher

Choudhary

2018

International Journal of Damage Mechanics

View full text Add to dashboard Cite

A detailed analysis has been performed for the prediction of long-term creep behaviour of tempered martensitic Grade 91 steel at 873 K using the microstructure-based creep damage mechanics approach. Necessary modifications have been made into the original kinetic creep law proposed by Dyson and McLean in order to account for the influence of microstructural damages arising from the coarsening of M23C6 and conversion of useful MX precipitates into deleterious Z-phase on creep behaviour of the steel. An exponential rate relationship has been introduced for the evolution of number density of MX precipitates with time. It has been shown that the developed model adequately predicts the experimental long-term creep strain–time as well as creep rate-time data. The role of Z-phase on long-term creep behaviour of Grade 91 steel has also been discussed.

show abstract

Study of creep–fatigue behavior in a 1000 MW rotor using a unified viscoplastic constitutive model with damage

Cited by 26 publications

References 23 publications

On the Plastic Strain Accumulation in Notched Bars During High-Temperature Creep Dwell

On the Plastic Strain Accumulation in Notched Bars During High-Temperature Creep Dwell

Fatigue–oxidation–creep damage model under axial-torsional thermo-mechanical loading

Prediction of long-term creep behaviour of Grade 91 steel at 873 K in the framework of microstructure-based creep damage mechanics approach

Contact Info

Product

Resources

About