Investigation of mechanical properties of nonwoven second generation composite material elaborated through a mixture of carbon fibers and filament lengths

Abstract : The current study aims to investigate the mechanical properties of ten different carbon fiber nonwoven reinforced thermoplastic composites. A design of experiments was carried out by using a Mixture Design methodology in order to produce nonwoven fabrics by carding and pre-needling. Composites were manufactured by compression molding using film stacking method. Tensile properties such as tensile modulus and tensile strength were investigated as function of proportion of fibers in nonwovens and direction of applied load. It was found that the mechanical properties of the composites were much higher in the Cross direction than in the Machine direction. It was observed that the mechanical properties are mainly influenced by fiber properties and orientation of fibers in the nonwovens. The tensile modulus was then modelled by multilinear regression resulting from the design analysis and Rule of Hybrid Mixtures (RoHMs). A good correlation between the experimental and the predicted values is observed.