Monotonic and Completely Reversed Cyclic Stress-Strain and Fatigue Behavior of Representative Aircraft Metals

摘要

Monotonic and cyclic stress-strain and fatigue behavior in the life range of approximately 10 to 100,000 cycles are experimentally determined for 2024-T4 and 7075-T6 aluminum alloys, SAE 4340 steel (quenched and tempered at 1000F), and titanium alloy 8-1-1. The purpose of the investigation is to establish the necessary materials information and base line fatigue data for cumulative damage studies. Plots of the fatigue life as function of elastic, plastic and total strain at half the fatigue life are presented for the four metals. The usual log-log linear relationships between fatigue life and the elastic and plastic components of strain do not satisfactorily fit the fatigue results, especially for the two aluminum alloys. Thus, it will be necessary to use the actual fatigue plots rather than simple power functions as the base line fatigue data for cumulative damage studies. (Author)