Volume 17, Issue 6 (November 1989)
A Method to Obtain Ideal Fatigue Crack Propagation for Steels
To predict fatigue crack growth rates under variable loading conditions, a new fatigue test method was developed. Fatigue crack propagation properties were studied for HT80, SM50B, and SUS304 steels. Test results showed that the acceleration of the crack propagation rate occurred at low ΔK regions when the intermittent compressive overload was applied. The maximum acceleration of crack propagation was dependent on both the frequency and amplitude, of the overload. When the compressive overload is frequently applied, the crack propagation rate becomes proportional to the second power of ΔK.
These accelerations of the crack propagation rate under compressive overloading conditions were discussed with respect to the deformation mode at the crack tip.