Fatigue Strength And Shot-peening

Author:  Akira Tange, Fumio Takahashi
Source:  Conf Proc: ICSP-10 Tokyo, Japan 2008
Doc ID:  2008080
Year of Publication:  2008
Abstract Improving fatigue strength by shot-peening, first of all, it is essential to understand the phenomenon of fatigue fracture. Unfortunately, in these days, there are still serious accidents caused by fatigue fracture. This would be due to both the difficulties of finding small defects causing fatigue fracture and the incomplete quantitative understanding of a notch sensitivity determined by hardness and stress ratio (including residual stress). In addition, the relation between processing conditions for shot-peening, residual stress and surface roughness is not always clear. However, by applying the theoretical approach of fracture mechanics, it has become possible to have clearer understanding of the residual stress distributions and the dimension of surface defect quantitatively for improving fatigue strength. In this paper, the relations between residual stress distributions by shot-peening and fatigue strength is discussed quantitatively. Keywords: fatigue, notch sensitivity, hardness, defect, shot-peening, residual stress

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