Effects of notch root radius and stress ratio on the fatigue crack propagation threshold for the short crack at the notch root

Akimitsu Seo, Masanobu Kubota, Yoshiyuki Kondo

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The crack growth threshold, ΔKth, for the short crack at the root of a long notch including the effects of notch root radius, ρ, and stress ratio, R, were investigated in this study. The pre-crack, with a depth of 0.15mm, was introduced at the root of a 2mm deep notch which had the root radius changed from 0.015mm to 15mm. A crack propagation test using the unloading elastic compliance method was carried out with the stress ratios of -1, 0 and 0.62-0.72 (high R). The material was normalized 0.25 % carbon steel. The change in ΔKth with the change in ρ was dependent on R. Under R = -1, there was a reduction in ΔKth when the notch root radius was greater than 0.5mm. On the other hand, for R = 0 and high R, ΔKth was almost constant regardless of ρ. Although ΔKth was different depending on the stress ratio and notch root radius, the effective crack growth threshold (ΔKeff)th was constant under all the test conditions. Therefore, the change in the crack growth behavior of the short crack at the notch root was dominated by the crack closure. The reduction in ΔKth in the relatively dull notch for R = -1 could also be explained by the change in the development of the crack closure during crack growth.

Original languageEnglish
Title of host publication19th European Conference on Fracture
Subtitle of host publicationFracture Mechanics for Durability, Reliability and Safety, ECF 2012
PublisherEuropean Conference on Fracture, ECF
ISBN (Print)978-5-905576-18-8
Publication statusPublished - Jan 1 2012
Event19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012 - Kazan, Russian Federation
Duration: Aug 26 2012Aug 31 2012

Publication series

Name19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012

Other

Other19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012
CountryRussian Federation
CityKazan
Period8/26/128/31/12

Fingerprint

Fatigue crack propagation
Crack propagation
Cracks
Crack closure
Unloading
Carbon steel

All Science Journal Classification (ASJC) codes

  • Safety, Risk, Reliability and Quality

Cite this

Seo, A., Kubota, M., & Kondo, Y. (2012). Effects of notch root radius and stress ratio on the fatigue crack propagation threshold for the short crack at the notch root. In 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012 (19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012). European Conference on Fracture, ECF.

Effects of notch root radius and stress ratio on the fatigue crack propagation threshold for the short crack at the notch root. / Seo, Akimitsu; Kubota, Masanobu; Kondo, Yoshiyuki.

19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012. European Conference on Fracture, ECF, 2012. (19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Seo, A, Kubota, M & Kondo, Y 2012, Effects of notch root radius and stress ratio on the fatigue crack propagation threshold for the short crack at the notch root. in 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012. 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012, European Conference on Fracture, ECF, 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012, Kazan, Russian Federation, 8/26/12.
Seo A, Kubota M, Kondo Y. Effects of notch root radius and stress ratio on the fatigue crack propagation threshold for the short crack at the notch root. In 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012. European Conference on Fracture, ECF. 2012. (19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012).
Seo, Akimitsu ; Kubota, Masanobu ; Kondo, Yoshiyuki. / Effects of notch root radius and stress ratio on the fatigue crack propagation threshold for the short crack at the notch root. 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012. European Conference on Fracture, ECF, 2012. (19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012).
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