On the Possible Relaxation of the ASTM E1921 and ASTM E1820 Standard Specifications with Respect to the Use of the Mini-CT Specimen

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On the Possible Relaxation of the ASTM E1921 and ASTM E1820 Standard Specifications with Respect to the Use of the Mini-CT Specimen. / Lambrecht, Marlies; Chaouadi, Rachid; Uytdenhouwen, Inge; Scibetta, Marc.

In: Materials Performance and Characterization, Vol. 9, No. 5, MPC20190217, 07.08.2020, p. 593-607.

Research output: Contribution to journalSpecial issue

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@article{267a88c504cf43e98adafa3e51020d15,
title = "On the Possible Relaxation of the ASTM E1921 and ASTM E1820 Standard Specifications with Respect to the Use of the Mini-CT Specimen",
abstract = "Specimen miniaturization is gaining a lot of interest in the fracture mechanics community thanks to recent methods accounting for specimen size correction. In particular, the miniature compact tension (mini-CT) specimen is gaining large international interest for irradiated surveillance materials used to monitor irradiation damage in reactor pressure vessels. Because of the limited available amount of some of these materials, eight mini-CT specimens can easily be machined from one broken Charpy specimen, avoiding the need of consuming surveillance materials. Specimen reorientation also becomes possible to investigate anisotropic effects. At this stage, ASTM E1921, Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range(Superseded), the standard for brittle fracture, and ASTM E1820, Standard Test Method for Measurement of Fracture Toughness (Superseded), the standard for ductile fracture, are used for this geometry, although it does not fully satisfy the requirements of the standards. In particular, the specifications on the specimen dimensions relative to the specimen width are tight, given that the tolerances are a fraction of the specimen width. Given that the actual dimensions of the specimen are taken into account in the calculations, the analysis described in this article shows that the tight dimensional accuracy is not necessary. Moreover, given the limited thickness of the specimen, the curvature of the fatigue precrack tends to deviate from a quasi-straight front. As a result, a large number of mini-CT specimens do not fulfill the standard requirements with respect to crack front curvature. Previous tests demonstrated that actual cracks excessive curvature lead to similar results when compared with artificial fatigue quasi-straight cracks. The objective of this article is to experimentally demonstrate that some of the standard requirements can be relaxed without jeopardizing the quality of test data, in terms of master curve and crack resistance curve.",
keywords = "ASTM E1921, ASTM E1820, mini-C(T)",
author = "Marlies Lambrecht and Rachid Chaouadi and Inge Uytdenhouwen and Marc Scibetta",
note = "Score=10",
year = "2020",
month = "8",
day = "7",
doi = "10.1520/MPC20190217",
language = "English",
volume = "9",
pages = "593--607",
journal = "Materials Performance and Characterization",
issn = "2379-1365",
publisher = "ASTM International",
number = "5",

}

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TY - JOUR

T1 - On the Possible Relaxation of the ASTM E1921 and ASTM E1820 Standard Specifications with Respect to the Use of the Mini-CT Specimen

AU - Lambrecht, Marlies

AU - Chaouadi, Rachid

AU - Uytdenhouwen, Inge

AU - Scibetta, Marc

N1 - Score=10

PY - 2020/8/7

Y1 - 2020/8/7

N2 - Specimen miniaturization is gaining a lot of interest in the fracture mechanics community thanks to recent methods accounting for specimen size correction. In particular, the miniature compact tension (mini-CT) specimen is gaining large international interest for irradiated surveillance materials used to monitor irradiation damage in reactor pressure vessels. Because of the limited available amount of some of these materials, eight mini-CT specimens can easily be machined from one broken Charpy specimen, avoiding the need of consuming surveillance materials. Specimen reorientation also becomes possible to investigate anisotropic effects. At this stage, ASTM E1921, Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range(Superseded), the standard for brittle fracture, and ASTM E1820, Standard Test Method for Measurement of Fracture Toughness (Superseded), the standard for ductile fracture, are used for this geometry, although it does not fully satisfy the requirements of the standards. In particular, the specifications on the specimen dimensions relative to the specimen width are tight, given that the tolerances are a fraction of the specimen width. Given that the actual dimensions of the specimen are taken into account in the calculations, the analysis described in this article shows that the tight dimensional accuracy is not necessary. Moreover, given the limited thickness of the specimen, the curvature of the fatigue precrack tends to deviate from a quasi-straight front. As a result, a large number of mini-CT specimens do not fulfill the standard requirements with respect to crack front curvature. Previous tests demonstrated that actual cracks excessive curvature lead to similar results when compared with artificial fatigue quasi-straight cracks. The objective of this article is to experimentally demonstrate that some of the standard requirements can be relaxed without jeopardizing the quality of test data, in terms of master curve and crack resistance curve.

AB - Specimen miniaturization is gaining a lot of interest in the fracture mechanics community thanks to recent methods accounting for specimen size correction. In particular, the miniature compact tension (mini-CT) specimen is gaining large international interest for irradiated surveillance materials used to monitor irradiation damage in reactor pressure vessels. Because of the limited available amount of some of these materials, eight mini-CT specimens can easily be machined from one broken Charpy specimen, avoiding the need of consuming surveillance materials. Specimen reorientation also becomes possible to investigate anisotropic effects. At this stage, ASTM E1921, Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range(Superseded), the standard for brittle fracture, and ASTM E1820, Standard Test Method for Measurement of Fracture Toughness (Superseded), the standard for ductile fracture, are used for this geometry, although it does not fully satisfy the requirements of the standards. In particular, the specifications on the specimen dimensions relative to the specimen width are tight, given that the tolerances are a fraction of the specimen width. Given that the actual dimensions of the specimen are taken into account in the calculations, the analysis described in this article shows that the tight dimensional accuracy is not necessary. Moreover, given the limited thickness of the specimen, the curvature of the fatigue precrack tends to deviate from a quasi-straight front. As a result, a large number of mini-CT specimens do not fulfill the standard requirements with respect to crack front curvature. Previous tests demonstrated that actual cracks excessive curvature lead to similar results when compared with artificial fatigue quasi-straight cracks. The objective of this article is to experimentally demonstrate that some of the standard requirements can be relaxed without jeopardizing the quality of test data, in terms of master curve and crack resistance curve.

KW - ASTM E1921

KW - ASTM E1820

KW - mini-C(T)

UR - https://ecm.sckcen.be/OTCS/llisapi.dll/overview/42487262

U2 - 10.1520/MPC20190217

DO - 10.1520/MPC20190217

M3 - Special issue

VL - 9

SP - 593

EP - 607

JO - Materials Performance and Characterization

JF - Materials Performance and Characterization

SN - 2379-1365

IS - 5

M1 - MPC20190217

ER -

ID: 7053696