SYMPOSIA PAPER Published: 01 January 1985

Effects of Load Gradient on Applicability of a Fatigue Crack Growth Rate-Cyclic Relation


The use of a cyclic J to characterize fatigue crack growth rates for conditions where the assumptions of linear elastic fracture mechanics are violated is addressed. In particular, the effects of the load gradient on the applicability of a cyclic J are examined. Experiments were conducted to quantify fatigue crack growth rates and cyclic J on modified compact tension specimens of A533B steel. Fatigue cycling at constant load amplitude where the cyclic J increases as the crack extends and constant displacement amplitude where the cyclic J decreases as the crack extends were performed. It is found that prior cyclic crack tip history affects the fatigue crack growth rate only as a consequence of influencing the extent of crack closure. Accounting for crack closure by requiring J equal to zero at the crack opening load results in excellent correlation between the fatigue crack growth rate and cyclic J for a wide range of loading conditions.

Author Information

Jolles, M
Fracture Mechanics Section, Naval Research Laboratory, Washington, DC
Price: $25.00
Contact Sales
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Developed by Committee: E08
Pages: 381–391
DOI: 10.1520/STP34264S
ISBN-EB: 978-0-8031-4933-5
ISBN-13: 978-0-8031-0225-5