Paper number 1034

MODELING APPROACH OF MICROBUCKLING MECHANISM DURING CURE IN A CARBON EPOXY LAMINATE

Ch. Jochum¹, J-C. Grandidier² and M. Potier-Ferry¹

1Laboratoire de Physique et de Mécanique des Matériaux, UMR CNRS 7554,
Institut Supérieur de Génie Mécanique et Productique,
Université de Metz, Île du Saulcy, F-57045 METZ CEDEX 01.
2Laboratoire de Modélisation Mécanique et Mathématiques Appliquées
Université de Poitiers, bd 3, Téléport 2, BP 179, 86960 FUTUROSCOPE cedex

Summary

In this work, the mechanism of fibre positioning imperfections observed in carbon epoxy composites is studied. The fibre waviness is established as being the consequence of a fibre microbuckling phenomenon created by resin shrinkage during the hot phase of the thermosetting reaction instead of final cooling stage of cure process. In order to have a good description of this fundamental mechanism, both experimental and theoretical studies on single fibre composite specimens are done. The physical and mechanical aspects of the thermosetting reaction are established for the 120°C isothermal cure. The structure is described through a model of a fibre embedded in an infinite matrix medium and which is generalized to the case of laminates. The microbuckling possibilities are analyzed through a matrix response determined experimentally during it's cure by a DMTA method.

Keywords

waviness defects, cure process, microbuckling during cure, single fibre composite specimen, gelation, shrinkage, long fibre laminate, viscoelasticity.