Accession Number : AD0681026
Title : Fatigue Crack Propagation in a High-Strength Steel under Constant Cyclic Load with Variable Mean Loads
Descriptive Note : Final rept.
Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC
Personal Author(s) : Crooker, T W ; Lange, E A
PDF Url : AD0681026
Report Date : 29 Nov 1968
Pagination or Media Count : 22
Abstract : Fatigue crack propagation studies were conducted on a 9Ni-4Co-0.25C high-strength steel using a constant cyclic load and variable mean loads. The load ratio, R, was varied from +0.5 to -1.0. Fatigue crack growth rates were analyzed using the crack tip stress-intensity factor, K. The results show that mean loads exert a strong secondary influence on fatigue crack propagation. Data were fitted to two crack propagation equations which seek to account for mean loads. Both equations significantly reduced, but did not eliminate, the layered scatter caused by mean loads.
Descriptors : *STEEL, COBALT ALLOYS, CRACK PROPAGATION, FATIGUE(MECHANICS), LOADS(FORCES), NICKEL ALLOYS
Subject Categories : Metallurgy and Metallography
Distribution Statement : APPROVED FOR PUBLIC RELEASE