The effects of bias angle and fiber volume fraction on the mechanical properties of filament-wound, polypropylene-glass tubes

This thesis discusses the uninterrupted, filament winding of a continuous, fiber- reinforced, polypropylene cylinder using raw materials (not a prepreg) at start-up. The objective was to increase the understanding of the process by yielding defensible conclusions regarding its operation in achieving engineering structures possessing high mechanical properties. Primarily, the effects of the bias angle wrap and the fiber volume fraction on the mechanical properties of the composite laminates were studied. The experimental values were compared against a theoretical mechanics model for the force resultants and the moduli of the laminate. It was found that the highest tensile and flexural strengths were achieved for the lowest bias angle value obtainable, 54°. Similarly, it was also found that the highest tensile and flexural moduli belonged to the 54° tube. The strength and modulus for fiber volume fractions of 0.34, 0.37, and 0.46 did not appear to vary significantly from one sample to the other. Therefore, it was determined that the fiber volume fraction was not a controlling factor in regards to the mechanical properties of the products in this experiment.