Challenges of modelling the extrusion process

The numerical simulation of the (co-)extrusion process involves many complex phenomena in order to accurately model the behaviour of the extruded material and sometimes, the fluid surrounding it. Such mechanisms can be viscoelastic behaviours, fluid structure interaction, thermal effects, large deformations, turbulent flow surrounding the fibres. These complex physics can now be simulated but, sometimes, they require large calculation time. The challenge is now to guide users towards proper modelling to include only the necessary physics while keeping the simulation time as short as possible. The right balance between physics and simulation time, i.e. modelling, is the key challenge for the new generation of codes.