Damping Properties of Vapor-Grown Carbon Fiber Composites

The objective of this paper is to investigate analytically and experimentally the dynamic mechanical properties of vapor grown carbon fiber (VGCF)/thermoplastic composites. The experimental results show that, as predicted, very low fiber aspect ratios may produce significant improvements in damping. Since VGCF have submicron diameters and lengths, with a fiber aspect ratio, l/d = 19, good dynamic properties are obtained by using them as reinforcement in a thermoplastic. Fiber length distributions and orientation in the injection molded samples are determined by scanning electron microscopy (SEM). An analytical model based on the elastic-viscoelastic correspondence principle is developed to predict elastic properties in short fiber composites having a preferential fiber orientation in the direction of injection. The mechanical damping and storage modulus are analyzed experimentally by using a Dynamic Mechanic Analyzer (DMA).