Fatigue Damage and Life Prediction of Glass/Vinyl Ester Composites

Fatigue mechanisms and life time prediction of E-glass/vinyl ester composites are studied. Unnotched unidirectional composites subjected to tension-tension sinusoidal loading with a frequency of 1.5 Hz were employed. Quantitative damage data were obtained and analysed for the fatigue life prediction. S-N data and curve were constructed and fatigue mechanisms at different stress ranges were discussed in terms of stiffness reduction/fatigue modulus and quantitative damage. It was found that the micro-crack density increased logarithmically with increasing number of loading cycles. A model based on the fatigue modulus reduction was developed to predict an S-N curve using phenomenological parameters. The life time predictions were shown to be in good agreement with experimental results.