Hygrothermal characteristics of carbon fibre reinforced plastics

Abstract

The following account describes investigations of the moisture absorption characteristics of specimens prepared from a unidirentionally reinfonced sheet of carbon fibre reinforced plastic (CFRP), Fibredux 914C, which were subjected to a variety of environmental conditions. Experiments were undertaken over the approximate temperature range −70 to + 180° C, employing specimens containing moisture at levels between approximately 0 and 2 wt%. A scheme has been developed to assess the fractional length changes which might be anticipated in specimens containing different moisture contents resulting from a change of temperature, assuming no loss of moisture during the temperature change. Application of the analytical scheme to the experimental data has revealed the detailed dependence of specimen dimensions upon moisture content and temperature. The investigation has sewed to underline the importance of knowing the humidity of the environment in which a CFRP component has to operate, as well as its temperature, in order that it might be possible to predict its subsequent dimensional behaviour.