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Numerical modelling of Charpy-V notch test by local approach to fracture. Application to an A508 steel in the ductile-brittle transition range; Modelisation de l'essai Charpy par l'approche locale de la rupture. Application au cas de l'acier 16MND5 dans le domaine de transition

Abstract

Ferritic steels present a transition of the rupture mode which goes progressively of a brittle rupture (cleavage) to a ductile rupture when the temperature increases. The following of the difference of the transition temperature of the PWR vessel steel by the establishment of toughness curves makes of the Charpy test an integrating part of the monitoring of the French PWR reactors. In spite of the advantages which are adapted to it in particular its cost, the Charpy test does not allow to obtain directly a variable which characterizes a crack propagation resistance as for instance the toughness used for qualifying the mechanical integrity of a structure. This work deals with the establishment of the through impact strength-toughness in the transition range of the vessel steel: 16MND5 from a non-empirical approach based on the local approach of the rupture. The brittle rupture is described by the Beremin model (1983), which allows to describe the dispersion inherent in this rupture mode. The description of the brittle fissure is carried out by the GTN model (1984) and by the Rousselier model (1986). This last model has been modified in order to obtain a realistic description of the brittle damage in the case of  More>>
Authors:
Publication Date:
Jul 15, 2001
Product Type:
Thesis/Dissertation
Report Number:
FRNC-TH-6345
Resource Relation:
Other Information: TH: These sciences et genie des materiaux; 250 refs; Available from Ecole Nationale Superieure des Mines- Bibliotheque, 60 boulevard Saint Michel, 75272 - Paris Cedex 06 (France)
Subject:
36 MATERIALS SCIENCE; CHARPY TEST; DUCTILE-BRITTLE TRANSITIONS; FINITE ELEMENT METHOD; FRACTOGRAPHY; RECRYSTALLIZATION; RESEARCH PROGRAMS
OSTI ID:
20912835
Research Organizations:
Ecole Nationale Superieure des Mines, 75 - Paris (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR0605127074011
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
516 pages
Announcement Date:
Sep 24, 2007

Citation Formats

Tanguy, B. Numerical modelling of Charpy-V notch test by local approach to fracture. Application to an A508 steel in the ductile-brittle transition range; Modelisation de l'essai Charpy par l'approche locale de la rupture. Application au cas de l'acier 16MND5 dans le domaine de transition. France: N. p., 2001. Web.
Tanguy, B. Numerical modelling of Charpy-V notch test by local approach to fracture. Application to an A508 steel in the ductile-brittle transition range; Modelisation de l'essai Charpy par l'approche locale de la rupture. Application au cas de l'acier 16MND5 dans le domaine de transition. France.
Tanguy, B. 2001. "Numerical modelling of Charpy-V notch test by local approach to fracture. Application to an A508 steel in the ductile-brittle transition range; Modelisation de l'essai Charpy par l'approche locale de la rupture. Application au cas de l'acier 16MND5 dans le domaine de transition." France.
@misc{etde_20912835,
title = {Numerical modelling of Charpy-V notch test by local approach to fracture. Application to an A508 steel in the ductile-brittle transition range; Modelisation de l'essai Charpy par l'approche locale de la rupture. Application au cas de l'acier 16MND5 dans le domaine de transition}
author = {Tanguy, B}
abstractNote = {Ferritic steels present a transition of the rupture mode which goes progressively of a brittle rupture (cleavage) to a ductile rupture when the temperature increases. The following of the difference of the transition temperature of the PWR vessel steel by the establishment of toughness curves makes of the Charpy test an integrating part of the monitoring of the French PWR reactors. In spite of the advantages which are adapted to it in particular its cost, the Charpy test does not allow to obtain directly a variable which characterizes a crack propagation resistance as for instance the toughness used for qualifying the mechanical integrity of a structure. This work deals with the establishment of the through impact strength-toughness in the transition range of the vessel steel: 16MND5 from a non-empirical approach based on the local approach of the rupture. The brittle rupture is described by the Beremin model (1983), which allows to describe the dispersion inherent in this rupture mode. The description of the brittle fissure is carried out by the GTN model (1984) and by the Rousselier model (1986). This last model has been modified in order to obtain a realistic description of the brittle damage in the case of fast solicitations and of local heating. The method proposed to determine the parameters of the damage models depends only of tests on notched specimens and of the inclusion data of the material. The behaviour is described by an original formulation parametrized in temperature which allows to describe all the tests carried out in this study. Before using this methodology, an experimental study of the behaviour and of the rupture modes of the steel 16MND5 has been carried out. From the toughness tests carried out in quasi-static and dynamical conditions, it has been revealed that this steel does not present important unwedging of its toughness curve due to the velocity effect. In the transition range, local heating of about 150 C have been measured in the root of the notch as well as plastic deformations superior to 100%. After a fractography study allowing to identify the nature of the sites which lead to the cleavage initiation, the numerical study shows, particularly, the effect of the adiabatic heating and the taking into account of the growth of cavities around a second population of particles (carbides) on the ductile fissure. The application of the proposed methodology allows to describe the resilience data until middle energies of about 70 J. Beyond, an appearing weak dependency of the cleavage constraint with temperature has to be introduced. On the other hand, the evolving of the toughness can be described until middle values of 170 MPa/m without introducing dependency of the cleavage constraint with temperature. (O.M.)}
place = {France}
year = {2001}
month = {Jul}
}