On the Energy Release Rate of Fatigued Composites Subjected to Compressive Overloads

Abstract

The behavior of delaminated graphite/epoxy composites under variable amplitude compressive loading (spectrum loading) is studied. The delamination growth is monitored in real time during fatigue tests. Different variable amplitude compressive load spectra are applied. Calculations of the energy release rate, G, as a function of the delamination length, delamination position, and applied strain during the spectrum loading are performed. Numerical simulations are based on a mixed mode fatigue growth model that is not subjected to the thin film model restrictions. The higher energy release values during the overloads were associated to the formation of intralayer and interlayer cracks on the composite specimens. [S0094-4289(00)03004-8]