Volume 7, Issue 1 (January 2010)
Revisit of ASTM Round-Robin Test Data for Determining R Curves of Thin-Sheet Materials
This paper revisits the ASTM round-robin fracture test data obtained in 1979–1980 by ASTM Task Group E24.06.02 on Application of Fracture Analysis Methods. The fracture tests were conducted using thin-sheet compact tension [C(T)] specimens made of three materials—7075-T561 aluminum alloy, 2024-T351 aluminum alloy, and 304 stainless steel—and different specimen widths were employed in order to take account of in-plane specimen size effect on fracture toughness. Typical experimental data are reanalyzed, and crack growth resistance curves are developed in accordance with fracture test standards, ASTM E561-05 and ASTM E1820-08. Several useful results as well as the conditions under which the two standards can equivalently determine a geometry-independent resistance curve are obtained for the thin-sheet C(T) specimens.