A process simulation model for the manufacture of composite laminates from fiber-reinforced, polyimide matrix prepreg materials

Abstract

A numerical simulation model has been developed which describes the manufacture of composite laminates from fiber-reinforced polyimide (PMR-15) matrix prepreg materials. The simulation model is developed in two parts. The first part is the volatile formation model which simulates the production of volatiles and their transport through the composite microstructure during the imidization reaction. The volatile formation model can be used to predict the vapor pressure profile and volatile mass flux. The second part of the simulation model, the consolidation model, can be used to determine the degree of crosslinking, resin melt viscosity, temperature, and the resin pressure inside the composite during the consolidation process. Also, the model is used to predict the total resin flow, thickness change, and total process time. The simulation model was solved by a finite element analysis.

Experiments were performed to obtain data for verification of the model. Composite laminates were fabricated from ICI Fiberite HMF2474/66C carbon fabric, PMR-15 prep reg and cured with different cure cycles. The results predicted by the model correlate well with experimental data for the weight loss, thickness, and fiber volume fraction changes of the composite. An optimum processing cycle for the fabrication of PMR-15 polyimide composites was developed by combining the model generated optimal imidization and consolidation cure cycles. The optimal cure cycle was used to manufacture PMR-15 composite laminates and the mechanical and physical properties of the laminates were measured. Results showed that fabrication of PMR-15 composite laminates with the optimal cure cycle results in improved mechanical properties and a significantly reduced the processing time compared with the manufacturer's suggested cure cycle.