The effect of cyclic loading on the stiffness degradation of angle-ply composite laminates

An experimental investigation has been conducted to determine the effect of cyclic loading on the stiffness degradation of composite laminates. Specimens were tested in tension-tension fatigue at a frequency of 10 Hz and a stress ratio of 0.1, over a wide range of stress levels. The laminate employed for this investigation was made of graphite/epoxy in an angle-ply (+ or - 35)2s orientation. During this investigation both static and dynamic stiffness reduction data were recorded during constant amplitude fatigue testing, and the results are presented in tabular and graphical form.