{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T14:14:52Z","timestamp":1779372892102,"version":"3.53.1"},"reference-count":22,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2024,2,6]],"date-time":"2024-02-06T00:00:00Z","timestamp":1707177600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>In this article, we characterize and review the unusual lack of threshold in fatigue crack growth (FCG) behavior for some alloys at low values of stress intensity factor ranges \u0394K and its implications to damage-tolerant design approaches. This unusual behavior was first observed by Marci in 1996 in IMI 834 alloy. Conventional applications of linear elastic fracture mechanics to FCG analysis at constant R-ratio (or Kmax) assumes that (da\/dN) decreases monotonically with decreasing \u0394K and approaches the threshold value of \u0394Kth with (da\/dN) \u2264 10\u22127 mm\/cycle for a given R (or Kmax). However, instead of \u0394K threshold behavior, some materials exhibit plateau or acceleration in da\/dN rate with decreasing \u0394K for long cracks tested in both constant R and Kmax conditions. This unusual (da\/dN)-\u0394K behavior is only observed experimentally but not understood and represents a challenge to scientists and engineers to model the safe fatigue life prediction of structures under low amplitude vibrating loads.<\/jats:p>","DOI":"10.3390\/ma17040792","type":"journal-article","created":{"date-parts":[[2024,2,7]],"date-time":"2024-02-07T03:47:09Z","timestamp":1707277629000},"page":"792","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Unusual Fatigue Crack Growth Behavior of Long Cracks at Low Stress Intensity Factor Ranges"],"prefix":"10.3390","volume":"17","author":[{"given":"Daniel","family":"Kujawski","sequence":"first","affiliation":[{"name":"Mechanical and Aerospace Engineering, Western Michigan University, Kalamazoo, MI 49008, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Asuri K.","family":"Vasudevan","sequence":"additional","affiliation":[{"name":"TDA Inc., Falls Church, VA 22043, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,2,6]]},"reference":[{"key":"ref_1","unstructured":"(2015). 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