TENSILE BEHAVIOR OF SYMMETRIC AND ASYMMETRIC STRUCTURAL COMPOSITE FOAMS

摘要

Symmetric and asymmetric structural composite foams were produced by enclosing a foamed core between two composite skins. The effect of each layer thickness and composition was studied by using different amounts of chemical blowing agent (1 and 1.5%wt) and flax fibres (0, 15, 30%wt). The samples were produced by compression molding and characterized in terms of tension. Videos were also taken to determine the relations between stress-strain curves and changes in sample structure. The results show that for symmetric structures, both skins break simultaneously, whereas asymmetric foams present two consecutive skin breaks. From the stress-strain curves, several parameters are reported and discussed: Young's modulus, yield stress and the strain at which each layer breaks. As expected, increasing CBA content decreased all the properties, while increasing fibre content led to higher Young's modulus and lower strain at break.