Paper number 275

MODELLING OF TRANSVERSE CRACKING UNDER UNIAXIAL FATIGUE LOADING IN CROSS-PLY COMPOSITE LAMINATES : EXPERIMENTAL VALIDATION

C. Henaff-Gardin, I. Goupillaud, M.C. Lafarie-Frenot, S. Buhr

Laboratoire de Mécanique et de Physique des Matériaux, ENSMA, BP 109,
86960 FUTUROSCOPE CEDEX, FRANCE

Summary

The purpose of this study is to validate a previous analysis of a cross-ply laminate containing cracks in each layer and submitted to a thermomechanical in-plane loading. The application of this approach to the case of unidirectional mechanical fatigue of (0m/90n)s lay-ups allows to predict : - the fatigue cycle number necessary for the initiation of the first matrix cracks, - the kinetics of this damage, as well as the stage of saturation, in any cross-ply laminate submitted to any uniaxial fatigue loading. In this work, this approach is validated for two (0m/90n)s lay-ups and two fatigue loading amplitudes. From results obtained by 3D FEM calculations, an extension to (90m/0n)s laminates is proposed. This extension permits to obtain a good agreement between predicted and experimental crack density values at saturation but fails in reproducing fatigue cracking kinetics in such stacking sequences.

Keywords

CFRP, composite laminates, fracture mechanics, fatigue, mode I, transverse cracks, aerospace applications, durability.