A MODIFIED FRACTURE MECHANICS APPROACH TO METAL FATIGUE |
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| Authors: | D L DuQuesnay H Abdel-Raouf T H Topper A Plumtree |
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| Affiliation: | Department of Civil Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1;Department of Mechanical Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1;Department of Materials Engineering, Zagazig University, Egypt |
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| Abstract: | The fatigue lives, the fatigue limit stress ranges and fatigue notch factors for metallic specimens can be predicted using a modified fracture mechanics model for short cracks based on the combination of solutions for the non-uniform strains at the surface of a metal and the development of crack closure. The resulting local stress intensity factor exceeds that indicated by linear elastic fracture mechanics at short crack lengths. The model predicts a smooth and continuous variation of the fatigue notch factor with notch size between a lower bound of unity and an upper bound equal to the theoretical notch stress concentration factor. The model is verified using experimental data for a 2024-T351 aluminium alloy for smooth and notched specimens tested at various stress ratios. |
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