文档介绍：International Journal of Fatigue 23 (2001) 751–766
ate/ijfatigue
On some basic problems of fatigue research in engineering
Xiulin Zheng
Department of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, People’s Republic of China
Received 1 March 2001; received in revised form 19 April 2001; accepted 26 April 2001
Abstract
Research on the basic fatigue formula, the criterion for omitting small loads, the rule for cumulative fatigue damage, and models
for predicting the fatigue crack initiation (FCI) life and probability distribution under variable-amplitude loading prehensively
studied and summarized in the present paper. First, the formula for FCI life is given as a function of the equivalent stress amplitude,
and the procedures for investigating overload effects are introduced. Using the above formula to analyze test results of the overload
effect on FCI life yields the formula for FCI life containing the overload effect factor, z, which can be adopted to characterize the
load interaction effect when Miner’s rule is used pute the cumulative fatigue damage. Fatigue test results and analysis of
the underload effect show that the FCI threshold in the FCI life formula can be taken as the criterion for omitting small loads in
life prediction and pilation of the load spectrum. Then, the fatigue damage function is defined, the cumulative fatigue damage
can puted and the FCI life of structure members under variable-amplitude loading can be obtained by using Miner’s rule.
Procedures for predicting the probability distribution of FCI life or fatigue life are described and examples are introduced. Further-
more, factors affecting the value of z and the applicability of Miner’s rule are briefly discussed. Finally, further areas for fatigue
research are tentatively proposed. Most interest should be focused on research into generally applicable life prediction models and
the approach for fatigue reliability asse