Senior Laboratory -- Composites

Sample Plots from SLCURE Simulation

The following plots show the temperature and extent of cure profiles for a simulated composite cure cycle. The 1" thick composite is made up of vinyl ester resin (52.25%) and E-glass (42.75%) with the remaining 5% being voids within the part. The cure cycle consisted of heating the part to 60 deg C and maintaining that temperature for 60 minutes.

Temperature Profile

Due to the thickness of the part and the low thermal conductivity of the resin, the heat generated by the exothermic reaction of the resin is not adequately removed. The increase in temperature at the center increases the resin's rate of reaction, which in turn generates more heat. The resulting "exotherm" can cause severe damage to the part if not controlled properly.

Extent of Cure Profile

Once the resin with the composite part begins to exotherm (as observed by the great increase in temperature), the extent of cure of the resin rapidly approaches its greatest value. Notice that in the following graph, this maximum value is not 1. Research seems to indicate that the presence of glass fibers in the system reduces the maximum extent of cure of the resin. Unfortunately, this has yet to be verified by DSC experiments. You should also note that the surface resin does not completely cure. This is because the surface region of the composite is not heat transfer limited and the temperature of the resin remains near that of the heating water.

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