Determination of Fatigue Behavior of Nanostructure of Severe Shot-Peened A356.0

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Rahmani, Edris | 2014

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 46597 (08)
University: Sharif University of Technology
Department: Mechanical Engineering
Advisor(s): Farrahi, Gholamhossein
Abstract:
In this study a layer with compressive residual stress was created by severe shot peening and hence surface grains was changed to nanostructure. Fatigue life will be increased as a result of compressive residual stress. Surface roughness increase, is one of the disadvantages of severe shot-peening process. Re-shot-peening with the smaller shots and lower intensity is proposed for reducing surface roughness. Numerical simulation as a powerful method, used to investigate the effects of shot-peening parameters on the residual stress distribution, surface roughness and grain size. Obtained results indicate that more energy in process can improve residual stress distribution and grain size unlike surface roughness. Simulation result verified by experimental measurement of surface roughness and grain size. Results also show that surface roughness can be decreased by re-shot-peening with lower energy. Influence of severe shot-peening on the fatigue life studied by experimental tests and implies that in the high-cycle fatigue life, effect of severe shot-peening is significant, while in the low-cycle fatigue, effect of severe shot-peening is almost negligible
Keywords:
Fatigue Life ; Residual Stress ; Surface Roughness ; Grain Size ; Severe Shot-peening

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