INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
artículos
Título:
CTOD-R curve construction from surface displacement measurements
Autor/es:
N. GUBELJAK; CHAPETTI, M D; J. PREDAN; J. LANDES
Revista:
ENGINEERING FRACTURE MECHANICS
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2011 vol. 78 p. 2286 - 2297
ISSN:
0013-7944
Resumen:
The construction of a fracture resistance dR (or JR) curve requires the appropriate measurement
of crack-tip opening displacement (CTOD) as a function of crack extension. This
can be made by different procedures following ASTM E1820, BS7448 or other standards
and procedures (e.g., GTP-02, ESIS-P2, etc.) for the measurement of fracture toughness.
However, all of these procedures require standard specimens, displacement gauges, and
calibration curves to get intrinsic material properties. This paper deals with some analysis
and aspects related to the measurement of fracture toughness by observing the surface of
the specimen. Tests were performed using three-dimensional surface displacement measurements
to determine the fracture parameters and the crack extension values. These
tests can be conducted without using a crack mouth opening displacement-CMOD or
load-line displacement gauge, because CMOD can be calculated by using the displacement
of the surface points. The presented method offers a significant advantage for fracture
toughness testing in cases where a clip gauge is not easy to use, for example, on structural
components. Simple analysis of stereo-metrical surface displacements gives a load vs.
crack opening displacement curve. Results show that the initiation of stable crack propagation
can be easy estimated as the point of the curves deviation. It is possible to determine
the deviation point if the crack opening displacement measurements are close to
crack tip in the plastic zone area. The resistance curve, CTOD-R, is developed by the local
measurement of crack opening displacement (COD) in rigid body area of specimen. COD
values are used for the recalculation with the CMOD parameter as a remote crack opening
displacement, according to the ASTM standard.dR (or JR) curve requires the appropriate measurement
of crack-tip opening displacement (CTOD) as a function of crack extension. This
can be made by different procedures following ASTM E1820, BS7448 or other standards
and procedures (e.g., GTP-02, ESIS-P2, etc.) for the measurement of fracture toughness.
However, all of these procedures require standard specimens, displacement gauges, and
calibration curves to get intrinsic material properties. This paper deals with some analysis
and aspects related to the measurement of fracture toughness by observing the surface of
the specimen. Tests were performed using three-dimensional surface displacement measurements
to determine the fracture parameters and the crack extension values. These
tests can be conducted without using a crack mouth opening displacement-CMOD or
load-line displacement gauge, because CMOD can be calculated by using the displacement
of the surface points. The presented method offers a significant advantage for fracture
toughness testing in cases where a clip gauge is not easy to use, for example, on structural
components. Simple analysis of stereo-metrical surface displacements gives a load vs.
crack opening displacement curve. Results show that the initiation of stable crack propagation
can be easy estimated as the point of the curves deviation. It is possible to determine
the deviation point if the crack opening displacement measurements are close to
crack tip in the plastic zone area. The resistance curve, CTOD-R, is developed by the local
measurement of crack opening displacement (COD) in rigid body area of specimen. COD
values are used for the recalculation with the CMOD parameter as a remote crack opening
displacement, according to the ASTM standard.CTOD) as a function of crack extension. This
can be made by different procedures following ASTM E1820, BS7448 or other standards
and procedures (e.g., GTP-02, ESIS-P2, etc.) for the measurement of fracture toughness.
However, all of these procedures require standard specimens, displacement gauges, and
calibration curves to get intrinsic material properties. This paper deals with some analysis
and aspects related to the measurement of fracture toughness by observing the surface of
the specimen. Tests were performed using three-dimensional surface displacement measurements
to determine the fracture parameters and the crack extension values. These
tests can be conducted without using a crack mouth opening displacement-CMOD or
load-line displacement gauge, because CMOD can be calculated by using the displacement
of the surface points. The presented method offers a significant advantage for fracture
toughness testing in cases where a clip gauge is not easy to use, for example, on structural
components. Simple analysis of stereo-metrical surface displacements gives a load vs.
crack opening displacement curve. Results show that the initiation of stable crack propagation
can be easy estimated as the point of the curves deviation. It is possible to determine
the deviation point if the crack opening displacement measurements are close to
crack tip in the plastic zone area. The resistance curve, CTOD-R, is developed by the local
measurement of crack opening displacement (COD) in rigid body area of specimen. COD
values are used for the recalculation with the CMOD parameter as a remote crack opening
displacement, according to the ASTM standard.CMOD or
load-line displacement gauge, because CMOD can be calculated by using the displacement
of the surface points. The presented method offers a significant advantage for fracture
toughness testing in cases where a clip gauge is not easy to use, for example, on structural
components. Simple analysis of stereo-metrical surface displacements gives a load vs.
crack opening displacement curve. Results show that the initiation of stable crack propagation
can be easy estimated as the point of the curves deviation. It is possible to determine
the deviation point if the crack opening displacement measurements are close to
crack tip in the plastic zone area. The resistance curve, CTOD-R, is developed by the local
measurement of crack opening displacement (COD) in rigid body area of specimen. COD
values are used for the recalculation with the CMOD parameter as a remote crack opening
displacement, according to the ASTM standard.CMOD can be calculated by using the displacement
of the surface points. The presented method offers a significant advantage for fracture
toughness testing in cases where a clip gauge is not easy to use, for example, on structural
components. Simple analysis of stereo-metrical surface displacements gives a load vs.
crack opening displacement curve. Results show that the initiation of stable crack propagation
can be easy estimated as the point of the curves deviation. It is possible to determine
the deviation point if the crack opening displacement measurements are close to
crack tip in the plastic zone area. The resistance curve, CTOD-R, is developed by the local
measurement of crack opening displacement (COD) in rigid body area of specimen. COD
values are used for the recalculation with the CMOD parameter as a remote crack opening
displacement, according to the ASTM standard.CTOD-R, is developed by the local
measurement of crack opening displacement (COD) in rigid body area of specimen. COD
values are used for the recalculation with the CMOD parameter as a remote crack opening
displacement, according to the ASTM standard.COD) in rigid body area of specimen. COD
values are used for the recalculation with the CMOD parameter as a remote crack opening
displacement, according to the ASTM standard.CMOD parameter as a remote crack opening
displacement, according to the ASTM standard.