SYMPOSIA PAPER Published: 01 January 1997

Fracture Toughness Results and Preliminary Analysis for International Cooperative Test Program on Specimens Containing Surface Cracks


Specimens containing surface cracks were tested in either tension or bending to compare the stress intensity factor at failure with plane strain fracture toughness (KIc) in an International Cooperative Test Program. The material was heat treated to σys = 1 587 MPa and KIc = 54 MPan1/2. Because substantial stable crack growth occurred for some specimens, the test plan was modified to include detecting the onset of crack growth. It is shown that Pmax and the original fatigue precrack size cannot be employed to calculate Kmax for comparison with KIc when significant stable crack growth occurs. However, using Pinit (load at which stable crack growth is initiated) and the original fatigue precrack size to calculate Kmax or Kϕ=30° provides a very useful comparison with KIc. The influence of variations in fatigue precrack configuration on test results are also discussed.

Author Information

Reuter, WG
Idaho National Engineering Laboratory, Lockheed Martin Idaho Technologies Company, Idaho Falls, ID
Elfer, N
Lockheed Martin Corporation, Manned Space System, New Orleans, LA
Hull, DA
Engineering Material Research, Downsview, Ontario, Canada
Newman, JC
NASA Langley Research Center, Hampton, VA
Munz, D
University of Karlsruhe, Karlsruhe, Federal Republic of Germany
Panontin, TL
NASA Ames Research Center, Moffet Field, CA
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Developed by Committee: E08
Pages: 146–166
DOI: 10.1520/STP12306S
ISBN-EB: 978-0-8031-5374-5
ISBN-13: 978-0-8031-2410-3