SYMPOSIA PAPER Published: 01 January 2000

Fracture Toughness Testing with Notched Round Bars


A method to simplify fracture toughness testing and reduce testing costs is discussed. An alternative specimen geometry, the notched round bar (NRB), has been combined with a simpler testing methodology. A multispecimen technique using notched round bars with finite notch root radii ρ was applied to 2024-T351 and overaged 2024 aluminum alloy. No fatigue precracking was used. A graph of apparent fracture toughness Kρ versus the square root of notch root radius √ρ was extrapolated to ρ = 0, corresponding to a fatigue precracked configuration. The resulting fracture toughness values were the same as those obtained from ASTM E 399 tests. Apparent fracture toughness Jρ, determined from NRB J-R curves for overaged 2024, was graphed versus notch root radius ρ. The extrapolated value of fracture toughness was the same as that obtained from ASTM E 813 and E 1152 tests.

Author Information

Wilson, CD
Tennessee Technological University, Cookeville, TN
Landes, JD
The University of Tennessee, Knoxville, TN
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Developed by Committee: E08
Pages: 69–82
DOI: 10.1520/STP13396S
ISBN-EB: 978-0-8031-5418-6
ISBN-13: 978-0-8031-2617-6