A Critical Depth Criterion for the Evaluation of Long-Life Fatigue Strength Under Multiaxial Loading and a Stress Gradient

Flavenot, J. F.; Skalli, N.

doi:10.1016/b978-1-4832-8440-8.50186-1

Cited by 15 publications

(15 citation statements)

References 8 publications

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“…The hydrostatic stress reduces to an almost constant value towards the centre of the specimen. This result is consistent with the work of [12,14]. As the cycles increase, the stress from an initial peak distribution (N=1), reduces due to the cyclic softening behaviour of P91 steel [7,24], as illustrated in Figs.…”

Section: Notched Specimensupporting

confidence: 79%

“…Initial validation of the performance of the material model is conducted in Barrett et al [1,2] and the current application concerns the assessment of the multi-axial performance of the model. To this effect, a notched specimen model has been designed to cover a specific stress regime and the multi-axial capability of the hyperbolic sine material model is assessed by means of analysis of the trends observed in finite element (FE) simulations and comparison with similar work conducted in this field [12][13][14]. The CoffinManson (C-M) [15] relationship is used to predict failure of the notched specimen and to compare the life of a notched specimen with that of a smooth test specimen.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Notched Specimensupporting

confidence: 79%

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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“…However, it appears sensible to argue that under the presence of a rapidly varying stress field, as may be the case in some fretting fatigue configurations, a high‐localized maximum is insufficient and that high values of the initiation parameter must be sustained over a process zone in order for initiation to take place. Flavenot & Skalli 31 have defined a critical layer for characterizing the microstructural state of materials. They suggested that this critical layer is a constant for a specific material and could be related to microstructural dimensions such as grain size.…”

Section: Multiaxial Fatigue Models and The Process Zone Approachmentioning

confidence: 99%

The use of multiaxial fatigue models to predict fretting fatigue life of components subjected to different contact stress fields

Araújo

Nowell

Vivacqua

2004

Fatigue Fract Eng Mat Struct

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A B S T R A C T This work describes the application of multiaxial fatigue criteria based on critical plane and mesoscopic (Dang Van, 1973, Sciences et Techniques de lÁrmement, 47, 647-722) approaches to predict the fatigue initiation life of fretted components. To validate the analysis, several tests under closely controlled laboratory conditions are carried out in a Ti6Al-4V alloy. These classical Hertzian tests reveal a size effect where fretting fatigue lives vary with contact size. Experimentally available data for fretting fatigue of an Al-4Cu alloy are also used to assess the models. Neither the critical plane models nor the mesoscopic criterion considered can account for the effects of different contact stress fields on the initiation life, if the calculation is based only on highly stressed points on the surface. It is shown, however, that satisfactory results can be achieved if high values of the fatigue parameters are sustained over a critical volume.

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“…Biaxial fatigue analysis using the concept of a critical plane of maximum shear strain is very effective because the critical plane concept is based on the fracture mode or initiation mechanism of cracks. In the critical plane concept, after determining the maximum shear strain plane, many researchers define the parameter as a combination of the maximum shear strain (or stress) and normal strain (or stress) on that plane to correlate multiaxial fatigue lives for various strain ratios 2–6 . The following section reviews the critical plane approaches examined in this study.…”

Section: Introductionmentioning

confidence: 99%

Closure‐free biaxial fatigue crack growth rate and life prediction under various biaxiality ratios in SAE 1045 steel

Varvani‐Farahani

Topper

1999

Fatigue Fract Eng Mat Struct

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Biaxial fatigue tests were performed on thin‐walled tubular 1045 steel specimens in a test fixture that applied internal and external pressure and axial load. There were two test series, one in which constant amplitude fully reversed strains (CAS) were applied and another in which large periodic compressive overstrain (PCO) cycles causing strains normal to the crack plane were inserted in a constant amplitude history of smaller strain cycles. Ratios of hoop strain to axial strain of λ = −1, −0.625, −ν and +1 were used in each test series. Fatigue crack growth behaviours under CAS and PCO histories were compared, and revealed that the morphology of the fracture surface near the crack tip and the crack growth rate changed dramatically with the application of the compressive overstrains. When the magnitude of the compressive overstrains was increased, the height of the fracture surface irregularities was reduced as the increasing overstrain progressively flattened the fracture surface asperities near the crack tip. The reduced asperity height was accompanied by drastic increases in crack growth rate and decreases in fatigue life. Using a pressurizing device attached to the confocal scanning laser microscope (CSLM), crack opening measurements were obtained. Crack opening measurements showed that the biaxial cracks were fully open at zero internal pressure for block strain histories containing in‐phase PCO cycles of yield stress magnitude. Therefore, for the shear‐strained samples, there was no crack face interference and the strain intensity range was fully effective. For PCO tests (with biaxial strain ratios of −0.625 and +1), effective strain intensity data were obtained from tests with positive stress ratios for which cracks did not close. A number of strain intensity parameters derived from well‐known fatigue life parameters were used to correlate fatigue crack growth rates for the various strain ratios investigated. Predicted fatigue lifetimes based on a fatigue crack growth rate prediction program using critical shear plane parameters showed good agreement with the experimental fatigue life data.

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A Critical Depth Criterion for the Evaluation of Long-Life Fatigue Strength Under Multiaxial Loading and a Stress Gradient

Cited by 15 publications

References 8 publications

Multiaxial cyclic viscoplasticity model for high temperature fatigue of P91 steel

Multiaxial cyclic viscoplasticity model for high temperature fatigue of P91 steel

The use of multiaxial fatigue models to predict fretting fatigue life of components subjected to different contact stress fields

Closure‐free biaxial fatigue crack growth rate and life prediction under various biaxiality ratios in SAE 1045 steel

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