Anisotropy and holes in epoxy composite reinforced by carbon/glass and carbon/aramid hybrid fabrics: Experimental and analytical results

Abstract

This study is based on research into the effect of anisotropy and the presence of holes on mechanical properties and final fracture characteristics in uniaxial tensile testing of two laminates, one using a carbon/glass fiber hybrid fabric and the other a carbon/aramid fiber hybrid fabric in loading directions at 0°, 90° and ±45°. Both laminates were impregnated with epoxy vinyl ester thermosetting resin (Derakane Momentum™ 411-350). An analytical study assesses stress concentration using the Point Stress Criterion (PSC) and Average Stress Criterion (ASC). The results show the direct influence of anisotropy, holes and residual properties on all the parameters studied. With respect to failure theories, both PSC and ASC showed good agreement when the geometric K value was used.