The fatigue life determination of a component obtained by testing the real geometry is a time consuming and expensive task. Therefore, the prediction of the fatigue life of a part by means of finite element method (FEM) is a frequent procedure of component designing. This prediction consists of: stresses, loads and strength behaviour of the component material. As an input value for the material properties S/N curves are defined, which are based on test results. Fatigue tests on notched, as well as unnotched specimens under compression-tension loading are carried out in order to obtain the S/N curves of the investigated spring steel. Two groups of specimens are prepared: longitudinal and perpendicular relative to the rolling direction, both with two different tempering temperatures. A comparison among FEM simulation and testing results on the real leaf geometry is also given.
Keywords: spring steel, leaf spring, S/N curves, fatigue strength, FEM based simulation