Journal
INTERNATIONAL JOURNAL OF FATIGUE
Volume 48, Issue -, Pages 231-246Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.ijfatigue.2012.10.022
Keywords
Fatigue crack nucleation; Wavelets; Multi-time scaling; Crystal plasticity FEM
Funding
- Air Force Office of Scientific [FA-9550-09-1-045 2]
- National Science Foundation [CMMI-0800587]
- Div Of Civil, Mechanical, & Manufact Inn
- Directorate For Engineering [1136219] Funding Source: National Science Foundation
Ask authors/readers for more resources
This paper investigates microstructure and load sensitive fatigue behavior of Ti-6242 using cyclic crystal plasticity finite element (CPFE) simulations of statistically equivalent image-based microstructures. A wavelet transformation induced multi-time scaling (WATMUS) method [1,2] is used to perform accelerated cyclic CPFE simulations till crack nucleation, otherwise infeasible using conventional time integration schemes. A physically motivated crack nucleation model in terms of crystal plasticity variables [3] is extended in this work to predict nucleation. The crack nucleation model is based on dislocation pile-up and stress concentration at grain boundaries, caused by inhomogeneous plastic deformation in the polycrystalline microstructure. The model is calibrated and validated with experiments. The dependence of yield strength on the underlying grain orientations and sizes is developed through the introduction of an effective microstructural parameter Plastic Flow Index or PFI. To determine the effects of the microstructure on crack nucleation, a local microstructural variable is defined in terms of the surface area fraction of soft grains surrounding each hard grain or SAFSSG. Simulations with different cyclic load patterns suggest that fatigue crack nucleation in Ti-6242 strongly depends on the dwell cycle hold time at maximum stress. (C) 2012 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available