Study on Low-Cycle Fatigue Strength Reduction Factor

Abstract

The reduction in low-cycle fatigue strength due to the notch geometry was studied on carbon steel (SFVV1) and austenitic stainless steel (SUS 304).
Since the calculated low-cycle fatigue strength reduction factor (K_f) varies depending upon a given estimation method of nominal strain at the notch root area, a new evaluation method of nominal strain was developed from the experimental data on the circumferentially grooved specimens. The K_f value thus determined was shown to be consistent well with the FEM analysis of strain concentration factor, but was considerably lower than those specified in the ASME Code Sec. III above the 3S_m level.