Shear mode threshold for a small fatigue crack in a bearing steel

H. Matsunaga, N. Shomura, S. Muramoto, M. Endo

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51 Citations (Scopus)


The fatigue behaviour of small, semi-elliptical surface cracks in a bearing steel was investigated under cyclic shear-mode loading in ambient air. Fully reversed torsion was combined with a static axial compressive stress to obtain a stable shear-mode crack growth in the longitudinal direction of cylindrical specimens. Non-propagating cracks less than 1 mm in size were obtained (i) by decreasing the stress amplitude in tests using notched specimens and (ii) by using smooth specimens in constant stress amplitude tests. The threshold stress intensity factor ranges, ΔKIIth and ΔKIIIth, were estimated from the shape and dimensions of non-propagating cracks. Wear on the crack faces was inferred by debris and also by changes in microstructure in the wake of crack tip. These effects resulted in a significant increase in the threshold value. The threshold value decreased with a decrease in crack size. No significant difference was observed between the values of ΔK IIth and ΔKIIIth.

Original languageEnglish
Pages (from-to)72-82
Number of pages11
JournalFatigue and Fracture of Engineering Materials and Structures
Issue number1
Publication statusPublished - Jan 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering


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