Universal Journal of Mechanical Engineering Vol. 1(3), pp. 83 - 91
DOI: 10.13189/ujme.2013.010302
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Stress Raisers and Its Effect on Fatigue Sensitivity: A Study of Notch and Fretting Fatigue

M.A. Rahmat^1,*, R.N. Ibrahim¹, R.H. Oskouei^2
1 Department of Mechanical & Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia
² School of Computer Science, Engineering & Mathematics, Flinders University, Bedford Park, SA 5042, Australia

ABSTRACT

In this study, stress raisers (notches, fretting fatigue and a combination of notch and fretting) were taken into consideration as to its performance in reducing fatigue life. Reduction factor measurements using fatigue sensitivity, q as an effect of the respective stress raiser on fatigue lives were done. Finite element analyses on the consequence of clamping pressure on a notched geometry revealed a further increase in stress concentration at the notch tip for this specific geometry. However, fatigue tests revealed no significant difference in the fatigue lives between the notched and the combined notch and fretting fatigue. Fatigue notch sensitivity, q_n was found to be between 0.42 and 0.65 while a fretting notch-like sensitivity, q_f calculated from fretting fatigue results using a method by Wharton et al were 3.52 and 3.28 at torque levels 20 Nm and 50 Nm respectively. It was found that the stress concentration factor, k_t for the fretting condition was conservative in its value and did not correlate well with the actual fretting reduction factor, k_f. Finally, fractorgraphic analysis revealed significant wear for both fretting fatigue specimens and the combined notch and fretting fatigue. However, cracks were only found to originate from the notch tip for the combined notch and fretting fatigue at all alternating stress levels.

KEYWORDS
Fatigue, Stress Raiser, Notch Sensitivity, Fretting Fatigue

Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] M.A. Rahmat , R.N. Ibrahim , R.H. Oskouei , "Stress Raisers and Its Effect on Fatigue Sensitivity: A Study of Notch and Fretting Fatigue," Universal Journal of Mechanical Engineering, Vol. 1, No. 3, pp. 83 - 91, 2013. DOI: 10.13189/ujme.2013.010302.

(b). APA Format:
M.A. Rahmat , R.N. Ibrahim , R.H. Oskouei (2013). Stress Raisers and Its Effect on Fatigue Sensitivity: A Study of Notch and Fretting Fatigue. Universal Journal of Mechanical Engineering, 1(3), 83 - 91. DOI: 10.13189/ujme.2013.010302.