A path-dependent fatigue crack propagation model under non-proportional modes I and III loading conditions

Journal Article · Fri Jul 21 00:00:00 EDT 2017 · Engineering Fracture Mechanics

DOI:https://doi.org/10.1016/j.engfracmech.2017.07.026· OSTI ID:1376654

Mei, J. ^[1]; Dong, P. ^[1]; Kalnaus, S.  ^[2]; Jiang, Y. ^[2]; Wei, Z. ^[3]

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1. Univ. of Michigan, Ann Arbor, MI (United States)
2. Univ. of Nevada, Reno, NV (United States)
3. Tenneco, Grass Lake, MI (United States)

It has been well established that fatigue damage process is load-path dependent under non-proportional multi-axial loading conditions. Most of studies to date have been focusing on interpretation of S-N based test data by constructing a path-dependent fatigue damage model. Our paper presents a two-parameter mixed-mode fatigue crack growth model which takes into account of crack growth dependency on both load path traversed and a maximum effective stress intensity attained in a stress intensity factor plane (e.g.,KI-KIII plane). Furthermore, by taking advantage of a path-dependent maximum range (PDMR) cycle definition (Dong et al., 2010; Wei and Dong, 2010), the two parameters are formulated by introducing a moment of load path (MLP) based equivalent stress intensity factor range (ΔKNP) and a maximum effective stress intensity parameter KMax incorporating an interaction term KI·KIII. To examine the effectiveness of the proposed model, two sets of crack growth rate test data are considered. The first set is obtained as a part of this study using 304 stainless steel disk specimens subjected to three combined non-proportional modes I and III loading conditions (i.e., with a phase angle of 0°, 90°, and 180°). The second set was obtained by Feng et al. (2007) using 1070 steel disk specimens subjected to similar types of non-proportional mixed-mode conditions. Once the proposed two-parameter non-proportional mixed-mode crack growth model is used, it is shown that a good correlation can be achieved for both sets of the crack growth rate test data.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1376654
• Journal Information: Engineering Fracture Mechanics, Vol. 182, Issue C; ISSN 0013-7944
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Mixed mode crack growth
Multi-axial fatigue
Non-proportional loading
Moment of load path
Effective stress intensity factor
K plane
Path-dependent fatigue damage
Path-dependent cycle counting