Process simulation: Moulding processes

The properties of fibre-reinforced composites are significantly influenced by manufacturing parameters. Models to simulate these processes typically depend on the chosen reinforcement (short, discontinuous, or long fibres) and the considered moulding process. This chapter revisits some common composite moulding technologies, some associated constitutive models to describe the material behaviour during these processes, and some numerical approaches for implementing them. Different flow regimes are identified, based on the fibre orientations and the resin flow kinematics. These include: (i) the flow of a simple dilute fibre suspension; (ii) the flow of a concentrated fibre suspension, as encountered in injection moulded materials; (iii) entangled suspensions where the fibres and the suspending fluid have different velocities, as encountered in sheet moulding compounds; and finally (iv) the case where fibres remain almost at rest and the resin flows around them, such as resin transfer moulding or prepreg compression moulding. Constitutive models are derived for each flow regime and a case study is provided to demonstrate the effectiveness of each approach.