A method to numerically predict the loading ratio dependency of long crack propagation rates under cyclic loading

摘要: Abstract The investigation of cyclic crack propagation rates (CPR) for different loading ratios is very elaborate. A multiscale numerical approach to predict high cycle fatigue (HCF) strength a ferritic-pearlitic steel has been modified be applicable the calculation its CPR. original involves series and mechanism-based analytical models. Microstructural features material are statistically characterized generation synthetically representative volume element (RVE) models microstructure. combined isotropic kinematic hardening model crystal plasticity used include microdeformation behavior under in model. simulation with numerous these equivalent RVEs results indicator parameter (FIP) fields which differ from one RVE other. With regard weakest link theory, only highest FIP each extracted further calculations. Theses FIPs distributed by an extreme value distribution function can uniquely described two parameters. These parameters determine rate. For comparison experiment simulations, concept proposed links globally applied stress amplitude on intensity factor. needs calibrated CPR conducted arbitrarily chosen ratios. validation achieved prediction at ratio. obtained values good agreement experimental results.