Prediction of low-cycle fatigue behaviour of GFRP: an experimental approach

Abstract

Fatigue tests conducted on “Scotchply-1000” under constant stress range ΔS or constant strain range Δ∈ gave essentially the same life when the stress range was normalized by the ultimate strength (ΔS/σu) and the strain range was normalized by the fracture strain (Δ∈/∈f). Fatigue cycling of either type produces a progressive decrease in the modulus of elasticity which is a linear function of log N. An empirical relation of the type used to predict the low-cycle fatigue of metals was selected to predict the low-cycle fatigue behaviour of GFRP materials. Agreement between the experimental results and the predictions of the empirical relation was found to be good. A general method of evaluating the constants from a limited number of fatigue tests has been suggested. Further generalization of the constants and their correlation with the tensile properties of the material may be possible with the availability of more data on the fatigue of composite materials.