Frictional resistance of thermoset prepregs and its influence on honeycomb composite processing

Abstract

Abstract A testing device was developed to measure the frictional resistance of woven prepregs at temperatures and consolidation pressures typical of those used in honeycomb sandwich processing. To demonstrate the use of this new device, the frictional resistance of three woven carbon fibre/epoxy prepreg systems were measured. It was found that frictional characteristics vary between prepregs and that these differences do not exhibit a one-to-one correlation with the viscosity of the matrix resin or prepreg. Further, prepreg exhibiting lesser frictional resistance showed greater degrees of core crush. These observed differences were shown to be dependent on both resin viscosity and distribution of the resin on the prepreg surface. Finally, integration of these results into the manufacture of test panels suggests that core crush observed in honeycomb production may be strongly influenced by frictional resistance changes during cure.