Effect of Fabric Weave Geometry and Strand Orientation on Mode I Interlaminar Toughness of Glass-Epoxy Laminates

Abstract

nterlaminar toughness of glass-epoxy laminates subjected to Mode I quasi static loading was investigated. The influence of reinforcement geometry on GIc was focused. Six different laminates reinforced with INTERGLAS 2/2 twill fabrics of three different areal densities and two strand orientations, θ, were tested. The considered fabric areal densities were 390g/m2, 280g/m2 and 163g/m2, and strand orientations θ=0°/90° and θ=±45°. For laminates with θ=±45° strand orientation a statistically significant difference in the means of the interlaminar toughness GIc was noticed for all three laminates i.e. reinforced with the fabrics of areal densities 163 g/m2 and 280 g/m2, and 390 g/m2. For laminates with strand orientation θ=0°/90° a significant difference in Gic means was noticed for laminates with fabrics of areal densities 163 g/m2 and 280 g/m2, and 280 g/m2 and 390 g/m2, only. For groups of laminates reinforced with a particular fabric type a statistically significant difference in the means of GIc was found each time when laminates differed in the strand arrangement θ regardless the way the GIc values were calculated. Fracture analysis done with the help of a SEM did not explained the observed differences in GIc values.