Evolution des propriétés mécaniques de matériaux composites verre/polyester gelcoates en milieu marin

Glass-fiber reinforced polyester composites with gelcoat are widely used in nautical construction despite the lack of knowledge concerning their durability when immersed in water. This study deals especially with the influence of the osmotic process of degradation on the evolution of the mechanical properties of orthotropic materials, subjected to accelerated ageing tests. This evolution is experimentally evaluated by performing a non destructive test procedure, the vibrational modal analysis, whose results are additionally confirmed by quasi-static mechanical tests (bending and shear). Although gelcoat blistering has no effect on the mechanical properties of the structure, considerable changes are observed in the elastic moduli and in the ultimate stresses, particularly in a direction perpendicular to the reinforcement, when an osmotic delamination of the laminate plies occurs.