Variable amplitude very high cycle fatigue of 17-4PH steel with a stepwise S-N curve
Bernd M. Schönbauer, M. Fitzka, Ulrike Karr, H. Mayer
Abstract
High and very high cycle fatigue (VHCF) tests were performed with 17-4PH stainless steel under constant amplitude (CA) and variable amplitude (VA) loading at load ratios of −1 and 0.05. Stepwise (duplex) S-N curves were determined with failure from surface inclusions above the transition stress amplitude, σtr, and from the interior below σtr. Similar σtr for CA and VA loading were found. VA failure occurred at Miner damage sums between 0.1 and 0.9 (surface failure) and 0.2 and 2.2 (internal failure). Omission of stress amplitudes less than 60% of the maximum amplitude is allowable for VA studies in the VHCF regime.
Topics & Concepts
AmplitudeMaterials scienceFatigue testingStress (linguistics)Duplex (building)Constant (computer programming)MetallurgyStructural engineeringComposite materialPhysicsEngineeringOpticsChemistryPhilosophyComputer scienceDNABiochemistryProgramming languageLinguisticsFatigue and fracture mechanicsFire effects on concrete materialsHigh Temperature Alloys and Creep