Characterization and Simulation of the Damage Accumulation in the Very High Cycle Fatigue (VHCF) Regime in a Metastable Austenitic Stainless Steel Based on the Resonant Behavior

摘要

The damage mechanisms of a metastable austenitic stainless steel (AISI304) in the VHCF regime are experimentally evaluated and modeled on a mesoscopic level. The martensite volume fraction induced by means of a monotonic predeformation and its inhomogeneous distribution along the cross-section of the specimens due to surface friction influence the transient behavior of the material and its fatigue life. Fatigue tests on flat samples are carried out at test frequencies of ～ 100 Hz and ～ 20 kHz. The underlying microstructural effects, such as dislocation dynamics, are described in connection with the resonant behavior by means of a numerical simulation on the basis of the boundary element method. The simulation model takes into account the grain orientation and thus the position of possible slip planes as well as individual elastic stiffness of the grains, resulting from the elastic anisotropy.