SYMPOSIA PAPER Published: 01 January 1993

Fatigue Damage Due to Sub-Threshold Load Cycles Between Periodic Overloads


Overloads separated by below-threshold minor cycles are applied to ASTM A588 steel specimens. Fatigue crack propagation data were recorded and acoustic emission (AE) signals were monitored throughout each test. Estimates of crack growth based on a linear summation are less than experimentally observed rates, even when below-threshold cycles are conservatively assumed damaging. Acoustic emission data provide additional evidence that below-threshold cycles within a variable amplitude load history contribute to fatigue damage. The intensity of the AE signals increases with the number of minor cycles between overloads, even though all minor cycles are below the threshold stress intensity.

Author Information

Zhou, Z
Research and Development, Digital Logging, Inc., Tulsa, OK
Zwerneman, FJ
Oklahoma State University, Stillwater, OK
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: 45–53
DOI: 10.1520/STP15076S
ISBN-EB: 978-0-8031-5255-7
ISBN-13: 978-0-8031-1874-4