Multiple Repeated Low-Cycle Torsional Fatigue of Carbon Steel under controlled Strain

In the Case of S45C Steel

Abstract

The low-cycle torsional fatigue tests under multiple repeated strains have been carried out by using an annealed carbon steel S45C, and the test results were used to investigate the applicability of the fatigue fracture criteria based on varying plastic strains as well as on hysteresis energy which was introduced in this paper instead of varying plastic strains. The values of fatigue lives obtained from these fatigue fracture criteria were compared with those calculated from the linear damage criterion.
As the main conclusion, the values of cumulative damage obtained from the fatigue fracture criteria based on varying plastic strains and hysteresis energy were slightly closer to unity than those calculated from the linear damage criterion. Therefore, the above two fatigue fracture criteria are considered applicable to the low-cycle torsional fatigue test results under multiple repeated strains. Furthermore, the values of cumulative damage obtained from the above fatigue fracture criteria were almost similar to the test resutls carried out previously by the authors under multiple repeated loads by using a carbon steel S45C.