Accession Number : AD0777999

Title :   Application of the J Integral to Crack Initiation in a 2024-T351 Aluminum Alloy,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Griffis,C. A. ; Yoder,G. R.

Report Date : 03 APR 1974

Pagination or Media Count : 27

Abstract : The J integral has been successfully applied as a fracture initiation criterion for 2024-T351 aluminum alloy. A heat-tinting technique was used for quantitative measurement of crack extension at selected points on the load-deflection curve. In three-point bend tests incorporating six specimen configurations the critical J values (J(Ic)) at the onset of crack movement differ by at most 15 percent and yield a mean K(Ic) value of 30.9 plus or minus 1.2 ksi/(in. superscript 1/2). The relationship between instantaneous J value and crack extension is independent of initial crack length over the range of crack sizes investigated. J-integral values associated with maximum load (5 to 15 percent crack growth), unlike J(Ic), show a strong dependence on specimen thickness. (Author)

Descriptors :   *Fracture(Mechanics), *Aluminum alloys, Test equipment, Geometry, Crack propagation

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE