Improved probabilistic model for fracture toughness prediction for nuclear pressure vessel steels

Марголин, Б. З.; Gulenko, A. G.; Shvetsova, V. A.

doi:10.1016/s0308-0161(98)00083-0

Cited by 72 publications

(51 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This simple expression which is similar to that used by Margolin in his model for brittle fracture initiated from particles (Margolin et al, 1998) shows that for a given stress state the strain necessary to nucleate microcracks strongly increases with temperature. It shows also that crack nucleation is favoured by stress state conditions, such as those of a crack tip, leading to high stress triaxiality ratio.…”

Section: Micromechanisms Of Fracturesupporting

confidence: 59%

Development of the Local Approach to Fracture over the Past 25 years: Theory and Applications

Pineau

2006

Int J Fract

170

View full text Add to dashboard Cite

This review paper is devoted to the local approach to fracture (LAF) for the prediction of the fracture toughness of structural steels. The LAF has been considerably developed over the past two decades, not only to provide a better understanding of the fracture behaviour of materials, in particular the failure micromechanisms, but also to deal with loading conditions which cannot easily be handled with the conventional linear elastic fracture mechanics and elastic-plastic fracture mechanics global approaches. The bases of this relatively newly developed methodology are first presented. Both ductile rupture and brittle cleavage fracture micromechanisms are considered. The ductile-to-brittle transition observed in ferritic steels is also briefly reviewed. Two types of LAF methods are presented: (i) those assuming that the material behaviour is not affected by damage (e.g. cleavage fracture), (ii) those using a coupling effect between damage and constitutive equations (e.g. ductile fracture). The micromechanisms of brittle and ductile fracture investigated in elementary volume elements are briefly presented. The emphasis is laid on cleavage fracture in ferritic steels. The role of second phase particles (carbides or inclusions) and grain boundaries is more thoroughly discussed. The distinction between nucleation and growth controlled fracture is made. Recent developments in the theory of cleavage fracture incorporating both the effect of stress state and that of plastic strain are presented. These theoretical results are applied to the crack tip situation to predict the fracture toughness. It is shown that the ductile-to-brittle transition curve can reasonably be well predicted using the LAF approach. Additional applications of the LAF approach methods are also shown, including: (i) the effect of loading rate and prestressing; (ii) the influence of residual stresses in welds; (iii) the mismatch effects in welds; (iv) the warm-prestressing effect. An attempt is also made to delineate research areas where large improvements should be made for a better understanding of the failure behaviour of structural materials.

show abstract

Section: Micromechanisms Of Fracturesupporting

confidence: 59%

Development of the Local Approach to Fracture over the Past 25 years: Theory and Applications

Pineau

2006

Int J Fract

170

View full text Add to dashboard Cite

show abstract

“…Nowadays the most widely used models are those derived from the work by Beremin (1983) (see also Margolin et al 1998). Assuming that the material contains a population of microdefects (inclusions, martensite-austenite (M.A.)…”

Section: Statistical Models For Cleavage Fracture-beremin Modelmentioning

confidence: 99%

Modeling ductile to brittle fracture transition in steels—micromechanical and physical challenges

Pineau

2008

Int J Fract

View full text Add to dashboard Cite

Both scientists and engineers are very much concerned with the study of ductileto-brittle transition (DBT) in ferritic steels. For historical reasons the Charpy impact test remains widely used in the industry as a quality control tool to determine the DBT temperature. The transition between the two failure modes, i.e. brittle cleavage at low temperature and ductile fracture at the upper shelf occurs also at low loading rate in fracture toughness tests. Recent developments have been made in the understanding of the micromechanisms controlling either cleavage fracture in BCC metals or ductile rupture by cavity nucleation, growth and coalescence. Other developments have also been made in numerical tools such as the finite element (FE) method incorporating sophisticated constitutive equations and damage laws to simulate ductile crack growth (DCG) and cleavage fracture. Both types of development have thus largely contributed to modeling DBT occurring either in impact tests or in fracture toughness tests. This constitutes the basis of a modern methodology to investigate fracture, which is the so-called local approach to fracture. In this study the micromechanisms of brittle cleavage fracture and ductile rupture are firstly shortly reviewed. Then the transition between both modes of failure is investigated. It is shown that the DBT behavior observed in impact tests or in fracture toughness specimens can be reasonably well predicted using modern theories on brittle and ductile fracture in conjunction with FE numerical simulations. The review includes a detailed study of a number of metallurgical parameters contributing to the variation of the DBT temperature. Two main types of steels are considered : (i) quenched and tempered bainitic and martensitic steels used in the fabrication of pressurized water reactors, and (ii) modern high-toughness line-pipe steels obtained by chemical variations and optimized hot-rolling conditions. An attempt is also made to underline the research areas which remain to be explored for improving the strength-toughness compromise in the development of steels.

show abstract

“…An equation similar to Eq. (1) was developed from a phenomenological analysis based on the Eshelby model [12], which was later further developed by models that incorporated stresses from dislocation pile-up (e.g., Margolin et al [13]). These equations were expressed in terms of the overall stress measures; they also contained shape functions originating from simple models.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Stress and Strain Fields in and around Inclusions of Various Shapes in a Cylindrical Specimen Loaded in Tension

Neimitz¹,

Janus²

2016

Archives of Metallurgy and Materials

View full text Add to dashboard Cite

AnAlysIs of stress And strAIn fIelds In And Around InclusIons of vArIous shApes In A cylIndrIcAl specImen loAded In tensIon.A numerical analysis is performed of the stress field in and around inclusions of various shapes. Inclusions both stiffer and more compliant than the metal matrix are analysed. The critical stresses required for inclusion fracture are estimated after observation of cavities and inclusions by scanning electron microscopy. Real inclusions were observed after performing uniaxial loading to different amounts of overall strain. The material tested was Hardox-400 steel.

show abstract

Improved probabilistic model for fracture toughness prediction for nuclear pressure vessel steels

Cited by 72 publications

References 14 publications

Development of the Local Approach to Fracture over the Past 25 years: Theory and Applications

Development of the Local Approach to Fracture over the Past 25 years: Theory and Applications

Modeling ductile to brittle fracture transition in steels—micromechanical and physical challenges

Analysis of Stress and Strain Fields in and around Inclusions of Various Shapes in a Cylindrical Specimen Loaded in Tension

Contact Info

Product

Resources

About