INTERNAL DAMPING OF SHORT-FIBER REINFORCED POLYMER MATRIX COMPOSITES

Abstract

This paper describes an analytical study to optimize the internal damping of short-fiber polymer matrix composites. Two different analytical methods—force balance model and finite-element numerical scheme were used to obtain numerical results. The loss factor is optimized in terms of many important parameters such as; fiber aspect ratio, the angle θ between the applied tensile load and the fiber direction, stiffness ratio between the fiber and matrix materials and the damping ratio between the fiber and matrix materials. The numerical results show that, for given fiber and matrix materials and given fiber volume fraction, there exists an optimum fiber aspect ratio and an optimum angle θ for maximum damping of the composite. The predicted optimum aspect ratios lie in the range of actual aspect ratios for whiskers and microfibers for small fiber damping and increases as the damping ratio between the fiber and matrix increases. The predicted optimum angle θ lies between 0 and 30°.