EXPERIMENTAL INVESTIGATION OF FLOW-THROUGH MULTILAYERED PREFORMS

This research investigates resin flow phenomena through preforms compo sed of multiple layers of reinforcement material. Two complete studies were performed: the first investigates the effect of varying the orde r of lay-up of a fixed number of plies, and the second studies the imp act of varying the thickness of the individual layers of a thick prefo rm. In each case, a set of compression experiments were first performe d to characterize the preforms so that in-situ layer thicknesses can b e calculated. Next, flow experiments were performed upon the preforms to determine the permeability and flow front behavior. In the first st udy, it was found that the weighted average scheme provides a reasonab le estimate for the effective permeabilities of the preforms, with err ors ranging from 14.2% to 23.8%. In the second study, however, the wei ghted average scheme was found to provide only a rudimentary estimate of the permeability, with an error that was seen to increase in magnit ude during the course of each experiment. In addition, computer simula tions were performed for the second study, which show the possibility of deriving transverse permeability values without direct measurement, although significant errors in inlet pressures were once again eviden t.