Three-dimensional finite element analysis for non-synchronized cure of thick composite laminates

A three-dimensional finite element model was established and verified for the description of curing process of thick composite laminates. Temperature, degree of cure, viscosity, resin volume fraction and thickness reduction ratio during the curing process were calculated for a 400-ply AS4/3501-6 laminate. Numerical results manifest that the peak temperature which is 49 K higher than the dwell temperature appears at the laminate's central ply; the changes of the temperature and degree of cure are not synchronized along the z-direction; the overshoot and quick-curing area is found evidently in the central part of the laminate; the viscosity varies greatly and the curing time is curtailed in this area, which prevent the spare resin in this area and under-part of the laminate flowing into the bleeder; the fact that the non-average distribution of the resin volume in the laminate stems from the existing of this area in the cure cycle, and the resin volume fraction is about 41% in the surface and 46.5% in the bottom which contact with the bleeder and the tool respectively; the approximate value of thickness reduction ratio is 15.7%.