Fatigue Life Estimation of FRP under Random Loading

Abstract

Investigation was made on the estimation method of fatigue life for FRP under various random load patterns generated with a micro-computer. Both the constant stress amplitude and the random loading tests were carried out by a hydraulic fatigue testing machine.
The distributions of peak stress amplitude and power spectral density were investigated in order to identify the statistical nature of random load being applied on the test specimen.
The probability density distribution of peak stress was evaluated by the two-parameter Weibull distribution for convenience and the Zero-crossing method was used for counting the number of cycles of random load.
The test results showed that the fatigue life under the Gaussian narrow-band and wide-band random loads could be estimated to some extent by the modified equivalent stress amplitude method based upon Miner's rule.