Calculation of S-N Curves for Different Mean Stresses on the Basis of “PHYBALmean” for the Quenched and Tempered Steel SAE 4140

Abstract

Abstract Recently, a couple of methods for the physically based fatigue life calculation of metallic materials were developed at the Institute of Materials Science and Engineering at the University of Kaiserslautern. The focus of these “PHYBAL”-methods is the reduction of the necessary experiments in comparison to the conventional determination of fatigue data. The application of the “PHYBAL”-method requires a limited number of high-precision fatigue experiments. In addition to conventional mechanical stress-strain hysteresis measurements temperature and electrical resistance measurements have to be carried out to characterize the cyclic deformation behaviour. So far the “PHYBAL”-versions “PHYBALW” (σW = endurance limit), “PHYBALLIT ” (LIT = load increase test), “PHYBALSB ” (SB = scatter bands) and “PHYBALmean ” (mean = mean stress) are available and were successfully applied on different unalloyed carbon steels as well as austenitic steels, cast irons and light alloy metals.