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

Abstract

Aspects that affect the manufacture ofaeroengine components in carbon fibre reinforced epoxyresin composite material are described and in particular.factors influencing the process of consolidation ofpreimpregnated material laminates to final componentform are critically assessed. Attention is drawn to theneed both to acquire a full understanding of the physicsof the consolidation process and to obtain quantitativeprocess control data for efficient development andsubsequent production of new components.All the variables associated with the processof laminate consolidation are dependent on basic matrixresin characteristics especially its cure advancement andthe consequent effect on the resin viscosity at allstages of a moulding cycle. To quantify the matrix resinchernorheological behaviour, methods for the generation ofmathematical models for the cure and viscosity changesundergone by a dicyandiamide (DICY) cured epoxy resinsystem are described. By the use of these mathematicalmodels a program for use on a personal computer has beenwritten by means of which the cure,exotherTnic heatgeneration and viscosity of the resin may be simulatedunder both isothermal and linear temperature rampconditions.Examples are included of the application of themodels in the solution of problems encountered in theautoclave process for composoite material components