Effect of large deformation on creep property evaluation by small-specimen bending tests

Tu, Shan‐Tung; Zhuang, Fakun; Zhou, Guo‐Yan; Sun, Wei

doi:10.1016/j.ijpvp.2016.02.009

Cited by 11 publications

(3 citation statements)

References 42 publications

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“…1,2 However, such a method involves extracting a considerable amount of material from the component. 10 Compared with traditional creep specimens undergoing solely uniaxially tensile loading, small specimens under constant loading show nonuniform stresses and strains, such as small punch testing (SPT) specimens, 3-point bending specimens, and clamped beam bending testing (CBT) specimens. To cope with this dilemma, small specimen testing technique (SSTT) rises and develops rapidly.…”

Section: Introductionmentioning

confidence: 99%

“…9 However, the measurement accuracy of SSTT seems insufficient in many occasions because of a lack of fundamental understanding. 10 Compared with traditional creep specimens undergoing solely uniaxially tensile loading, small specimens under constant loading show nonuniform stresses and strains, such as small punch testing (SPT) specimens, 3-point bending specimens, and clamped beam bending testing (CBT) specimens. The difference in loading configuration may give rise to the coappearance of multiple creep deformation mechanisms within the same specimen.…”

Section: Introductionmentioning

confidence: 99%

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Effect of stress regime‐dependent creep behaviour on measurement of creep strain rate based on small specimen techniques

Zhang

Bai

et al. 2018

Fatigue Fract Eng Mat Struct

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Small specimen creep testing technique has become a hot topic of research as bulk materials are not available in many occasions. The stress distributions in the small specimens such as small punch and 3‐point bending specimens are essentially nonuniform. As it is known, the creep deformation/damage accumulation mechanisms exhibited at a high stress regime are not the same as the ones at a lower stress regime for many engineering alloys. The potential measurement errors because of stress regime‐dependent creep behaviour, however, has not been considered in the determination of the creep parameters based on small specimen testing in the previous studies. In this paper, 2 kinds of materials that show different Norton's parameters at the corresponding stress regimes are examined. A simple case of 2‐bar structure is firstly adopted to illustrate the measurement error of creep strain rate because of stress regime‐dependent creep behaviour. Furthermore, clamped beam bending testing and small punch testing are investigated to demonstrate the significance of measurement error using the same materials. It is shown that an error of more than 8 times may occur near the transition point of creep deformation mechanism depending on specimen types and materials. Attention should thus be paid to the selection of stress level in the small specimen testing to avoid significant measurement errors.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of stress regime‐dependent creep behaviour on measurement of creep strain rate based on small specimen techniques

Zhang

Bai

et al. 2018

Fatigue Fract Eng Mat Struct

Self Cite

View full text Add to dashboard Cite

show abstract

“…One of the unique advantages the small punch creep test has is that one of the specimen dimensions (the thickness) is very small (~ 0.5mm), however, up to date, there are no universally accepted conversion techniques available for data interpretation, due to its complicated deformation and failure mechanisms [9]. Previous research has been carried out using miniaturised beam on pure bending specimen type [12][13][14][15], however, their method does not relate the damage parameters into correlation.…”

Section: Introductionmentioning

confidence: 99%

Determination of Creep Damage Properties from a Miniature Three Point Bending Specimen Using an Inverse Approach

Campbell-Brown

et al. 2017

KEM

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In this work, a novel method for determining the creep damage properties which can be used to represent the full life until failure from a miniature bending creep test specimen is developed based on a mathematical analysis and an inverse approach. Using the Kachanov-Rabotnov creep damage model, a mathematical expression for the deflection of a simply supported, rectangular miniature thin beam creep test specimen, under three-point bending (TPB), is derived. The outputs of these equations are iterated numerically using a MATLAB program. The time-dependent deflection curves are computed as the virtue TPB tests at various loads. The accuracy of the mathematical solutions is evaluated by the corresponding results obtained from finite element analysis. On this basis, an inverse method is then developed to obtain the creep and damage constants using a MATLAB optimisation scheme, where the primary creep is neglected. The results obtained for a power plant Grade 91 Cr steel is used for demonstration. The inverse approach developed has potential applications for assessing the high temperature material strength as part of a NDT procedure and for deriving the full life creep damage constitutive properties from a small volume of material, in particular, for various microstructure regions within a heat-affected zone of weldments, e.g. of power plant pipelines and aero-engine components.

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Influence of Grain Boundary Complexion on Deformation Mechanism of High Temperature Bending Creep Process of Cu Bicrystal

Reddy

Pal

2018

Trans Indian Inst Met

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Effect of large deformation on creep property evaluation by small-specimen bending tests

Cited by 11 publications

References 42 publications

Effect of stress regime‐dependent creep behaviour on measurement of creep strain rate based on small specimen techniques

Effect of stress regime‐dependent creep behaviour on measurement of creep strain rate based on small specimen techniques

Determination of Creep Damage Properties from a Miniature Three Point Bending Specimen Using an Inverse Approach

Influence of Grain Boundary Complexion on Deformation Mechanism of High Temperature Bending Creep Process of Cu Bicrystal

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