Analysis of isothermal curing uniformity of resin matrix composites based on dimensional analysis method

Non-uniformity of curing degree fields during curing process of composites is an important factor in causing residual thermal stress and curing shrinkage stress. In order to investigate the influences of process parameters on the curing uniformity during the curing molding process of resin matrix composite structures, a composite curing simulation model was built for Epon 862/W epoxy system firstly, and the model was verified. Then, the dimensionless form of heat transfer equation and curing kinetics equation about resin matrix composite structures was obtained by dimensional analysis. Finally, the influence rules of curing process temperature, convective heat transfer coefficient and thickness of the structure on curing uniformity of the composites were quantitatively analyzed by numerical simulation. The results show that the convective heat transfer coefficient has little effect on curing uniformity of composites under the condition of isothermal curing. There is a fitting function relationship between the dimensionless group characteristic time t_c/characteristic resin curing reaction time t_R and the difference of curing degree, and the function can be used in engineering calculation conveniently.