PSI - Issue 76

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ScienceDirect

Procedia Structural Integrity 76 (2026) 11–18

© 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Abstract A novel method to predict the fracture-mechanical fatigue limit based on simulated cyclic resistance curves is presented. Plasticity induced crack closure development, whose role in the fatigue limit analysis is emphasized due to its fast saturation, is modeled for short cracks under near-threshold loading via finite element analysis. Combined with the intrinsic threshold, the cyclic R-curve can be derived from the simulated crack closure response. The fatigue limit from crack arrest is determined by the tangency condition between nominal crack driving force and the cyclic R-curve. The fatigue limits predicted as a demonstration of the method are consistent with literature knowledge. The method can be employed to any geometry, material, crack, or loading configuration. 5th International Symposium on Fatigue Design and Material Defects Fatigue limit prediction with simulated cyclic resistance curves Kimmo Ka¨rkka¨inen a, ∗ , Joona Vaara b,c , Miikka Va¨nta¨nen d , Saana Bergman a , Bernd Scho¨nbauer e , Tero Frondelius a,b,c a Materials and Mechanical Engineering, Pentti Kaiteran katu 1, 90014 University of Oulu, Finland b R & D and Engineering, Wa¨rtsila¨, P.O.Box 244, 65101, Vaasa, Finland c Faculty of Built Environment, Tampere University, Korkeakoulunkatu 7, 33720, Finland d Global Boiler Works Oy, Lumijoentie 8, 90400 Oulu, Finland e Institute of Physics and Materials Science, BOKU University, Peter-Jordan-Str. 82, 1190 Vienna, Austria

Peer-review under responsibility of the scientific committee of the FDMD 2025 chairpersons Keywords: Crack closure; Fracture mechanics; Fatigue strength; Numerical modeling

1. Introduction

Predicting the fatigue limit of a mechanical component in service is crucial for safe operation. From the engineering point of view, the fatigue limit is among the most interesting design parameters. Many di ff erent models and predictions have been proposed to estimate the quantity (Kitagawa and Takahashi, 1976; El Haddad et al., 1979; Murakami and Endo, 1983; Taylor, 1999), most of which lack a solid physical basis making their transferability questionable. More recently, physically founded methods for predicting fatigue have been established. One such development is the cyclic resistance curve (Tanaka and Akiniwa, 1988; Maierhofer et al., 2014, 2018a; Vaara et al., 2025) following Elber’s (1970) discovery of fatigue crack closure, among other advances. This article focuses on the fracture mechanics approach to estimating the fatigue limit. Non-propagating cracks from defects are often systematically observed at the fatigue limit (Frost, 1959; Nisitani, 1968; Murakami and Endo,

∗ Corresponding author E-mail address: kimmo.karkkainen@oulu.fi (Kimmo Ka¨rkka¨inen).

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the FDMD 2025 chairpersons 10.1016/j.prostr.2025.12.281