Analysis and life prediction of a composite laminate under cyclic loading

A thermographic approach is applied to study the fatigue behavior of a Glass/Epoxy (G10/FR4) composite laminate. A series of uniaxial tension-compression and fully-reversed bending fatigue tests are performed at different stress levels and load ratios with both constant and variable amplitude loading. It is found that under the conditions tested, there is a fairly linear correlation between the rate of temperature rise obtained from the specimen and the time rate of hysteresis energy generation. It is shown that the slope of temperature rise obtained from the specimen increases steadily as the damage accumulates due to cyclic loading. It is also found that the slope of temperature rise is a useful parameter for the characterization of composite fatigue life in constant as well as variable amplitude loading. Several validation tests are performed both constant and variable amplitude loading, and the results are found to be in good agreement to those obtained from the experiments.