Fracture toughness comparison between a semielliptical surface crack in a 4PB plate and a through-thickness crack in a 3PB fracture toughness test specimen

Markku Nevalainen

Research output: Book/ReportReportProfessional

Abstract

Finite-element analyses were conducted for two 4PB plates with different size semielliptical surface cracks. The sizes of the surface cracks were: a/c = 0.357, c/b = 0.175, a/t = 0.125 (smaller surface crack) and a/c = 0.333, c/b = 0.375, a/t = 0.25 (larger surface crack). The dimensions of the plate, b = 101.6 mm and t = 50.8 mm, were the same in both analyses. The results of the analyses were compared to the results of a previously published analysis of a 3PB specimen by Nevalainen & Dodds (1995), with dimensions a/W = 0.5, W/B = 2, and W = 50.8 mm. Differences in the small-scale yielding, the J-Q behaviour and the effective crack-front length (effective specimen thickness in the case of the 3PB specimen) were found between the plate and the 3PB specimen. Two methods were proposed to calculate the fracture toughness of the plate. The experimental verification of the analysis results was carried out by testing the plate specimens with the larger surface crack and the 3PB specimens. The experimental results seemed to support the results of the finite-element analyses, although the test material properties did not match those of the analyses. The ductile-to-brittle transition curve of the test material was determined, and a difference of 29°C in the transition temperature, corresponding to the 100 MPaÖm fracture toughness, was found between the specimen types, the plates behaving in a more ductile way. A combined constraint and thickness correction was applied to the results, and it was found to reduce scatter and bring fracture toughness values to an equally low level.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages40
ISBN (Electronic)951-38-5046-3
ISBN (Print)951-38-5045-5
Publication statusPublished - 1997
MoE publication typeNot Eligible

Publication series

NameVTT Publications
PublisherVTT
No.303
ISSN (Print)1235-0621
ISSN (Electronic)1455-0849

Fingerprint

fracture toughness
crack
type specimen
comparison
test
temperature

Keywords

  • fractures (materials)
  • fracture strength
  • toughness
  • fracture properties
  • mechanical properties
  • nuclear power plants
  • finite element analysis
  • metal plates
  • cracks

Cite this

Nevalainen, Markku. / Fracture toughness comparison between a semielliptical surface crack in a 4PB plate and a through-thickness crack in a 3PB fracture toughness test specimen. Espoo : VTT Technical Research Centre of Finland, 1997. 40 p. (VTT Publications; No. 303).
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abstract = "Finite-element analyses were conducted for two 4PB plates with different size semielliptical surface cracks. The sizes of the surface cracks were: a/c = 0.357, c/b = 0.175, a/t = 0.125 (smaller surface crack) and a/c = 0.333, c/b = 0.375, a/t = 0.25 (larger surface crack). The dimensions of the plate, b = 101.6 mm and t = 50.8 mm, were the same in both analyses. The results of the analyses were compared to the results of a previously published analysis of a 3PB specimen by Nevalainen & Dodds (1995), with dimensions a/W = 0.5, W/B = 2, and W = 50.8 mm. Differences in the small-scale yielding, the J-Q behaviour and the effective crack-front length (effective specimen thickness in the case of the 3PB specimen) were found between the plate and the 3PB specimen. Two methods were proposed to calculate the fracture toughness of the plate. The experimental verification of the analysis results was carried out by testing the plate specimens with the larger surface crack and the 3PB specimens. The experimental results seemed to support the results of the finite-element analyses, although the test material properties did not match those of the analyses. The ductile-to-brittle transition curve of the test material was determined, and a difference of 29°C in the transition temperature, corresponding to the 100 MPa{\"O}m fracture toughness, was found between the specimen types, the plates behaving in a more ductile way. A combined constraint and thickness correction was applied to the results, and it was found to reduce scatter and bring fracture toughness values to an equally low level.",
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Fracture toughness comparison between a semielliptical surface crack in a 4PB plate and a through-thickness crack in a 3PB fracture toughness test specimen. / Nevalainen, Markku.

Espoo : VTT Technical Research Centre of Finland, 1997. 40 p. (VTT Publications; No. 303).

Research output: Book/ReportReportProfessional

TY - BOOK

T1 - Fracture toughness comparison between a semielliptical surface crack in a 4PB plate and a through-thickness crack in a 3PB fracture toughness test specimen

AU - Nevalainen, Markku

PY - 1997

Y1 - 1997

N2 - Finite-element analyses were conducted for two 4PB plates with different size semielliptical surface cracks. The sizes of the surface cracks were: a/c = 0.357, c/b = 0.175, a/t = 0.125 (smaller surface crack) and a/c = 0.333, c/b = 0.375, a/t = 0.25 (larger surface crack). The dimensions of the plate, b = 101.6 mm and t = 50.8 mm, were the same in both analyses. The results of the analyses were compared to the results of a previously published analysis of a 3PB specimen by Nevalainen & Dodds (1995), with dimensions a/W = 0.5, W/B = 2, and W = 50.8 mm. Differences in the small-scale yielding, the J-Q behaviour and the effective crack-front length (effective specimen thickness in the case of the 3PB specimen) were found between the plate and the 3PB specimen. Two methods were proposed to calculate the fracture toughness of the plate. The experimental verification of the analysis results was carried out by testing the plate specimens with the larger surface crack and the 3PB specimens. The experimental results seemed to support the results of the finite-element analyses, although the test material properties did not match those of the analyses. The ductile-to-brittle transition curve of the test material was determined, and a difference of 29°C in the transition temperature, corresponding to the 100 MPaÖm fracture toughness, was found between the specimen types, the plates behaving in a more ductile way. A combined constraint and thickness correction was applied to the results, and it was found to reduce scatter and bring fracture toughness values to an equally low level.

AB - Finite-element analyses were conducted for two 4PB plates with different size semielliptical surface cracks. The sizes of the surface cracks were: a/c = 0.357, c/b = 0.175, a/t = 0.125 (smaller surface crack) and a/c = 0.333, c/b = 0.375, a/t = 0.25 (larger surface crack). The dimensions of the plate, b = 101.6 mm and t = 50.8 mm, were the same in both analyses. The results of the analyses were compared to the results of a previously published analysis of a 3PB specimen by Nevalainen & Dodds (1995), with dimensions a/W = 0.5, W/B = 2, and W = 50.8 mm. Differences in the small-scale yielding, the J-Q behaviour and the effective crack-front length (effective specimen thickness in the case of the 3PB specimen) were found between the plate and the 3PB specimen. Two methods were proposed to calculate the fracture toughness of the plate. The experimental verification of the analysis results was carried out by testing the plate specimens with the larger surface crack and the 3PB specimens. The experimental results seemed to support the results of the finite-element analyses, although the test material properties did not match those of the analyses. The ductile-to-brittle transition curve of the test material was determined, and a difference of 29°C in the transition temperature, corresponding to the 100 MPaÖm fracture toughness, was found between the specimen types, the plates behaving in a more ductile way. A combined constraint and thickness correction was applied to the results, and it was found to reduce scatter and bring fracture toughness values to an equally low level.

KW - fractures (materials)

KW - fracture strength

KW - toughness

KW - fracture properties

KW - mechanical properties

KW - nuclear power plants

KW - finite element analysis

KW - metal plates

KW - cracks

M3 - Report

SN - 951-38-5045-5

T3 - VTT Publications

BT - Fracture toughness comparison between a semielliptical surface crack in a 4PB plate and a through-thickness crack in a 3PB fracture toughness test specimen

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Nevalainen M. Fracture toughness comparison between a semielliptical surface crack in a 4PB plate and a through-thickness crack in a 3PB fracture toughness test specimen. Espoo: VTT Technical Research Centre of Finland, 1997. 40 p. (VTT Publications; No. 303).