Comparison of theoretically and experimentally obtained fatigue life of components and specimens

: Grubisic, V.; Rupp, A.

Abstract
By fatigue tests under simulated operational loading conditions on forged spindels, hubs and axles of commercial vehicles as well as on test specimens taken from the components, the accuracy of the fatigue life prediction using conventional local strain approach was controlled. The material data for the life prediction were determined on the specimens machined out of the critical areas of the components. For the component tests service-like stress-time histories with mean stress variation (spindle) and without (hub) as well as load time histories with a Gaussian frequency distribution (axle, spindle) were used. The comparison of the calculated fatigue life of the components, based on the material data, with the experimentally obtained life shows, that a reliable fatigue life prediction with the conventional local strain approach is not achieved. The accuracy of the fatigue life prediction should be improved by a systematic, phenomenologic description of the decisive effects.