A review of creep analysis and design under multi-axial stress states

Yao, Hua-Tang; Xuan, Fu‐Zhen; Wang, Zhengdong; Tu, Shan‐Tung

doi:10.1016/j.nucengdes.2007.02.003

Cited by 105 publications

(38 citation statements)

References 101 publications

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“…Nondestructive inspection of the Takashi HONDA*, Takuya FUKAHORI*, Toshihide IGARI*, Yasuharu CHUMAN*, Takumi TOKIYOSHI* and Alan CF COCKS** surface and subsurface of pipe welds is carried out to examine the current damage, such as the cavity density, and the results are employed to guide simulation-based predictions. Several approaches can be taken in terms of damage simulation for Type IV failure, such as: continuum mechanics together with the stress-based time fraction or the ductility fraction of the material; creep fracture mechanics using the C* parameter (Yatomi et al, 2003, Segle et al, 2000; creep cavitation mechanics assuming diffusion (Rice, 1981); use of a grain boundary-resistance model (Fukahori, et al, 2013; and/or damage mechanics (Hyde et al, 2003, Yao et al, 2007. It remains difficult, however, to determine an optimal method for expressing both the microscopic and macroscopic phenomena of actual Type IV damage.…”

Section: Introductionmentioning

confidence: 99%

Creep damage analysis of simulated-HAZ notched bar specimens of modified 9Cr-1Mo steel

Honda

Fukahori

Igari

et al. 2017

Mechanical Engineering Journal

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From the standpoint of evaluating Type IV creep damage in the fine-grained heat affected zones (FGHAZ) of welded joints, an analysis method combining continuum damage mechanics (CDM) and a cavity nucleation model is proposed and applied to the creep testing of simulated-FGHAZ notched bars of mod. 9Cr-1Mo steel at 650℃. The Perrin-Hayhurst CDM model is adopted, which considers both softening by precipitate coarsening and damage by creep cavities. For the cavity nucleation model, a proposal by Gonzalez and Cocks is employed, which considers the randomness of grain-boundary-facet orientations in a polycrystalline material and gives a nucleation rate that is a function of the creep strain rate and a tri-axiality factor. The critical value of the damage parameter, corresponding to the initiation of micro cracks due to the coalescence of creep cavities, is expressed in terms of a critical value of the number density of creep cavities as determined from grain-boundary-resistance model simulations by the present authors. Creep rupture experiments have been conducted for circumferentially notched bar specimens with two kinds of notch acuities. The applicability of the combined CDM and cavity nucleation model is demonstrated by comparing the distribution of creep cavities observed experimentally with the simulation results. The final rupture life of the circumferentially notched bar specimens was also predicted to within a factor of two.

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Section: Introductionmentioning

confidence: 99%

Creep damage analysis of simulated-HAZ notched bar specimens of modified 9Cr-1Mo steel

Honda

Fukahori

Igari

et al. 2017

Mechanical Engineering Journal

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“…The most used empirical model for modelling rock creep is the Norton Power Law, proposed in 1929 (Pinto, 1995;Yao, 2007;Cruz, 2003). It represents a constant strain rate, characteristic of the secondary creep, as shown in the following equation:…”

Section: Empirical Modelsmentioning

confidence: 99%

“…The temperature term considers the Arrhenius Law (Yao, 2007), Q represents the activation energy, R is the universal gas constant and T 0 is a temperature of reference. The term ε 0 represents a material parameter and σ 0 is a stress threshold: above σ 0 or below σ 0 different values of n are used, according to different creep mechanisms.…”

Section: Empirical Modelsmentioning

confidence: 99%

“…It can make it impossible to be used in every day models where different parts are submitted to deviatoric stresses at different moments. Some attempts to avoid the explicit use of time have been made, like the Strain Hardening Law (Pinto, 1995;Yao, 2007) [6, 7]: where εdev is the deviatoric strain and α < 0 is a parameter of the material. This model has a mathematical singularity for zero deviatoric strain.…”

Section: Presence Of Time Parameter In Creep Equationsmentioning

confidence: 99%

“…Creep behaviour has been largely studied for the development of potash mines (Pinto, 1995), oil and gas well drilling (Mackay et al, 2007;Poiate et al, 2006) and nuclear waste disposal (Yao, 2007). Many constitutive equations, of empiric or rheological nature, have been proposed to describe the creep time-dependent strain (Pinto, 1995;Jaeger et al, 2007;Grainger, 2012) but all of them have their limitations regarding the physical meaning of the phenomenon.…”

Section: Introductionmentioning

confidence: 99%

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New constitutive equation for salt rock creep

Motta

Pinto

2014

Rem: Rev. Esc. Minas

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Drilling and stabilizing oil wells are important technological challenges for developing the Brazilian Pre-Salt deposits due to creep behaviour of salt rocks, which results in well closure and collapse. The objectives of this work are to analyse the currently used creep models and to propose a new empirical model that comprehends the three creep stages. This work suggests that a deep interpretation of Burger's rheological model, based on the physical parameters of creep phenomenon, should be investigated. The problem of the explicit presence of time in creep strain rate models is discussed. The new proposed model is able to reproduce models that describe the transient and the steady-state creep stages. However, its calibration should be careful, based on data from all these creep stages.Keywords: salt rock, oil drilling, creep models, rock mechanics. Resumo

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