Mechanical loss in a glass-epoxy composite

Abstract

Using a computer-controlled inverted torsion pendulum at frequencies near 1 Hz, we determined the mechanical losses in a uniaxially fiber-reinforced composite. The composite comprised glass fibers in an epoxy-resin matrix. We studied three fiber contents: 0,41, and 49 vol.%. Three mechanical-loss peaks appeared: above 300 K, near 200 K, and near 130 K. They correspond closely to α, β, and γ peaks found previously in many polymers. We failed to see a mechanical-loss peak for either the glass or the glass-resin interface. Between 300 and 4 K, the torsion modulus increased in the resin by a factor of 3.30 and in the 0.49 glass-epoxy by a factor of 2.37.