Study on fiber weight fraction effect on tensile modulus of polystyrene (PS) composites reinforced with short glass fiber (SGF) based on their fiber orientation

In this study, the tensile modulus of injection molded SGF/PS composites is investigated. The experimental and simulation results show, increasing of tensile modulus of these composites, is inconsistent with increasing of fiber content in high fiber weight fraction. This inconstancy is more distinguishable for fiber weight fractions greater than 40%wt of GF. To explain away this observation, the fiber orientation tensor of molded part is simulated. The behavior of a(11), the first orientation tensor component in filling flow direction, through the thickness of the part is obtained for different SGF/PS compositions. The consequent curves can explain the unexpected behavior and support this idea that the effects of fiber orientation should be considered in calculation of SFG composite properties.