Mechanical and electrical assessment of hybrid composites containing hollow glass reinforcement

A study has been performed on a series of hybrid composites with hollow glass-fibre reinforcement. The materials were tested both mechanically and electrically by means of microwave transmission measurements and waveguide measurements of fundamental electromagnetic properties. The main effect of adding hollow glass fibres to the hybrids was to reduce the measured value of dielectric constant, and it was shown that this could be combined with relatively high values of modulus if a stiff fibre such as Nicalon silicon carbide was used in the principal load-bearing direction. It was thus demonstrated that hybrid composites could be produced with a high levels of specific strength, modulus and damage tolerance combined with low dielectric constants, offering an attractive route for producing structurally sound electrically transparent components. (C) 1999 Elsevier Science Ltd. All rights reserved.