SYMPOSIA PAPER Published: 01 January 1985

Curve Determination Using Precracked Charpy Specimens and the Load-Drop Method for Crack Growth Measurements


J-R curves for two aluminum alloys, a titanium alloy, and a high strength, low alloy steel at two different strength levels were determined using precracked Charpy specimens. Three methods were used to measure crack growth: (1) multi-specimen, (2) compliance unloading, and (3) the “load-drop” method. The “load-drop” method assumes that crack growth occurs only after peak load has been attained and the amount which the load decreases after peak load is related to the size of the uncracked ligament. Comparisons between the three methods for all the materials show remarkably similar J-R curves. Also, using these curves to determine a JIc indicates very little difference between the “load-drop” method and the others in the measurement of toughness.

Author Information

Kapp, JA
U.S. Army Armament, Munitions, and Chemical Command, Armament Research and Development Center, Large Caliber Weapon Systems Laboratory, Benet Weapons Laboratory, Watervliet, NY
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Developed by Committee: E08
Pages: 281–292
DOI: 10.1520/STP34258S
ISBN-EB: 978-0-8031-4933-5
ISBN-13: 978-0-8031-0225-5