Paper number 581
ULTRASONIC STUDY OF THE ANISOTROPIC DAMAGE OF UNIDIRECTIONAL GLASS-EPOXY COMPOSITES DURING HYGROTHERMAL AGEING |
R. El Guerjouma, D. Ducret and J.C. Baboux
Groupe d'Etudes de Métallurgie Physique et de Physique des matériaux
GEMPPM UMR CNRS 5510 - INSA de Lyon -
20 Avenue Albert Einstein, 69621 Villeurbanne Cedex, France
Summary | The purpose of this work is to study using ultrasounds the effects of hygrothermal ageing on the elastic behaviour of an unidirectional glass-fibre reinforced epoxy matrix. Simulated ageing conditions are performed. The degradation processes resulting from 25 days ageing in distilled water at 70°C are considered. The damage is assessed quantitatively through the loss of stiffness in terms of elastic constants. In the framework of the thermodynamic of irreversible processes, a constitutive equation including a tensorial variable describing the damage phenomenon is used. Through the variation of the damage parameters, damage and its anisotropy are quantitatively assessed. This nondestructive characterization is conducted together with a SEM microstructural analysis to correlate ultrasonic macroscopic measurements to microscopic observations. |
Keywords | elastic properties, non-destructive evaluation, ultrasonics, ageing, damage, anisotropy, interface, polymer composites. |