Purpose – The purpose of this paper is to estimate the bending fatigue strengths/limits of smooth specimens and to quantitatively analyze the effects of residual stresses caused by surface enhancements. Design/methodology/approach – Rotating bending and three‐point bending fatigue tests were employed to investigate the effects of surface enhancements including shot peening and laser peening on fatigue strengths/limits of smooth specimens. The fatigue sources were determined by scanning electron microscopy (SEM). Findings – The two new concepts of surface fatigue strength/limit and subsurface fatigue strength/limit were proposed based on experimental results and the relationship of surface fatigue strength/limit to subsurface fatigue strength/limit was built. Research limitations/implications – This paper provides the estimation that fatigue strengths/limits of surface‐enhanced specimens is 1.34‐1.42 times that of un‐surface‐strengthened specimens for smooth ones without stress concentration. Originality/value – Based on the present investigation and analysis, an analysis for fatigue strengths/limits of surface‐enhanced smooth specimens can be used to design engineering components, particularly in the applications of aircraft industry.
International Journal of Structural Integrity – Emerald Publishing
Published: Aug 30, 2011
Keywords: Fatigue; Residual stresses; Smooth specimens; Local strength; Alloys; Surface properties of materials