Fatigue Life Prediction for High Strength AI-alloy under Variable Amplitude Loading

- Journal title : Transactions of the Korean Society of Mechanical Engineers A
- Volume 24, Issue 8, 2000, pp.2074-2082
- Publisher : The Korean Society of Mechanical Engineers
- DOI : 10.22634/KSME-A.2000.24.8.2074

Title & Authors

Fatigue Life Prediction for High Strength AI-alloy under Variable Amplitude Loading

Sim, Dong-Seok; Kim, Gang-Beom; Kim, Jeong-Gyu;

Sim, Dong-Seok; Kim, Gang-Beom; Kim, Jeong-Gyu;

Abstract

In this study, to investigate and to predict the crack growth behavior under variable amplitude loading, crack growth tests are conducted on 7075-T6 aluminum alloy. The loading wave forms are generated by normal random number generator. All wave forms have same average and RMS(root mean square) value, but different standard deviation, which is to vary the maximum load in each wave. The modified Forman's equation is used as crack growth equation. Using the retardation coefficient D defined in previous study, the load interaction effect is considered. The variability in crack growth process is described by the random variable Z which was obtained from crack growth tests under constant amplitude loading in previous work. From these, a statistical model is developed. The curves predicted by the proposed model well describe the crack growth behavior under variable amplitude loading and agree with experimental data. In addition, this model well predicts the variability in crack growth process under variable amplitude loading.

Keywords

Fatigue Crack Growth;Variable Amplitude Loading;Random Variable;Retardation Coefficient;Variability;Normal Distribution;

Language

Korean

Cited by

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