Mathematical models for the cure and viscosity characteristics of an epoxy resin and their applications in computer simulations of composite material manufacturing processes

Aspects that affect the manufacture of aeroengine components in carbon fibre reinforced epoxy resin composite material are described and in particular. factors influencing the process of consolidation of preimpregnated material laminates to final component form are critically assessed. Attention is drawn to the need both to acquire a full understanding of the physics of the consolidation process and to obtain quantitative process control data for efficient development and subsequent production of new components. All the variables associated with the process of laminate consolidation are dependent on basic matrix resin characteristics especially its cure advancement and the consequent effect on the resin viscosity at all stages of a moulding cycle. To quantify the matrix resin chernorheological behaviour, methods for the generation of mathematical models for the cure and viscosity changes undergone by a dicyandiamide (DICY) cured epoxy resin system are described. By the use of these mathematical models a program for use on a personal computer has been written by means of which the cure,exotherTnic heat generation and viscosity of the resin may be simulated under both isothermal and linear temperature ramp conditions. Examples are included of the application of the models in the solution of problems encountered in the autoclave process for composoite material components