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.
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