Abstract:
The objective of this study was to investigate the response of fibrous materials to compaction, since this response can affect significantly a number of important parameters, e.g. required tooling forces and fill-times, for some resin infusion manufacturing processes. A series of compression tests were carried out on both dry and wet (resin-impregnated) samples, at a number of different compaction speeds and to various final volume fraction levels. The materials were seen to exhibit a significant viscoelastic (stress relaxation) response, which changed according to whether the fibers were dry or wet. A thermomechanical model of fibrous material deformation was developed, incorporating the observed non-linear viscoelastic response, and the wet-dry change in response. The model is appropriate for the simple fibre compaction deformation which occurs during many of the liquid composite molding (LCM) processes. The model gives reasonably good results over a range of fiber volume fractions and compression speeds.