Effect of Strain Level on Cyclic Properties of S355 Steel

Fatigue strength of structural materials is estimated using results of experimental tests performed in the low cycle fatigue, among others. Computation models used for determination of strength are based on an assumption that there is a stabilization interval in low-cycle testing. Based on a review of literature, a conclusion can be drawn that stabilization of cyclic properties occurs rarely and applies to few metallic materials. Due to variability of loading conditions and the effect of low or high temperature, the occurrence of the phenomena of cyclic weakening or strengthening a material can be hardly anticipated explicitly and its course is affected by various factors related to the testing conditions. This creates important difficulties at the very handling of test results and during identification of models used in the course of fatigue strength computation.