Estimation of Fatigue Life Components By Proposed Mathematical Model | ||
Engineering and Technology Journal | ||
Article 1, Volume 28, Issue 19, September 2010, Pages 922-932 PDF (367.9 K) | ||
DOI: 10.30684/etj.28.19.15 | ||
Abstract | ||
In this study the fatigue behavior of an aluminum alloy designated 2024 – T3 under constant and variable amplitude of stresses is considered. The applied load adopted is a rotating bending one, the cross Section of the laboratory samples is circular with a diameter of (6.74mm). All tests were carried out under a stress ratio of R = - 1 and at room temperature condition. The study consists of two parts experimental and theoretical. The experimental part includes carrying out laboratory tests on two groups of specimens the first group was tested under constant stress amplitude to establish the S-N curve of the specimen's material, while the second group was tested under variable amplitude of stress to assess the effects of the accumulated fatigue damage. The theoretical part of the study includes a review of previous literature adopted to derive a theoretical and mathematical model depending upon the variation of the stresses obtainedby some previous theories, taking into consideration low and high stress levels, and even post yield. The derived model is denoted as elastic-plastic model for the evaluation of life time of machinery parts. The linear theory of Miner and the theory of Elastic Cracks Propagation are also studied throughout the theoretical part of the study. In order to assess the capability of the two theories with the derived model: a comparison is held between the experimented results and the results obtained by applying the two theories. It is noted that results obtained by applying the two theories are lower (underestimates) than those obtained from the experimental study and that results obtained by the suggested derived model are in better agreement than those obtained by the two theories. | ||
Keywords | ||
fatigue life; Aluminum Alloy; Mathematical Model | ||
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