Modeling of voids growth mechanisms during manufacturing composite laminates

Abstract

Manufacturing composite laminates made of epoxy resin matrix and long carbon fibers is divided into several operations. The most critical one is the cross-linking stage of the thermoset resin. During this phase, uncured prepreg plies’ stacking is transformed into a structural laminate by the achievement of a three dimensional macromolecular resin network. A question of matter is the quality of the polymerization process. If not optimized, it gives birth to defects in the bulk material, such as voids. These defects are considered as possible sources of damage in the composite parts. The aim of this work is to address void growth processes in thermoset composite laminates with dynamic modelling. Diffusion phenomena of gas molecules in resin are neglected for the moment, in order to study more easily viscous effects of the polymer on gas bubbles traped inside the fluid. Once model bases are fixed and validated, an optimization study is proposed to determine the best temperature and pressure cycles which permit to minimize the final void radius.