Process modelling of discontinuous long fibre carbon/polyether ether ketone composites: Defect prediction

A numerical model was developed to predict the defect formation during processing of compression moulded discontinuous long fibre carbon/polyether ether ketone composites. The model inputs are the material's temperature-dependant properties (through-thickness modulus and thermal shrinkage), the temperature distribution of the part during cooling and the applied moulding pressure. The material properties of carbon/polyether ether ketone prepreg were measured during cooling from melt using thermal analyses. The model was employed to identify regions on manufactured panels where pressure could be lost during cooling, which are prone to defect formation. Validation was performed by comparing the predicted defect areas against those found on flat panels moulded at pressures ranging from 10 to 110 bar. The model was then employed in a case study to show the importance of the cooling strategy in order to prevent defects on complex-shape components