Consolidation of carbon fiber laminae during polymer‐matrix composite fabrication, studied by electrical resistance measurement

The consolidation of carbon fiber epoxy‐matrix laminae during composite fabrication by lamination (involving consolidation, curing and cooling) was found to hastened and to occur to a greater extent by increasing the pressure. The consequence of better consolidation remained after curing and subsequent cooling. A higher pressure resulted in a lower throughthickness resistivity in a composite after curing and cooling. The extent of consolidation was quantitatively described by N / N o (the ratio of the number of fiber‐fiber contacts between adjacent laminae at a given time, divided by that at the start of consolidation), which was calculated from the measured through‐thickness electrical resistivity. From the variation of N / N o during heating in the process of consolidation, three stages of consolidation were observed. In the first stage, N / N o increased very gradually; in the second stage, N / N o increased abruptly; in the third stage, N / N o increased at a moderate rate.