3D Modeling of squeeze flows occurring in composite laminates

Abstract

Nowadays thermoplastic composite materials are more and more used due to their specific excellent mechanical properties and a good recyclability. However, many difficulties are encountered during their forming processes, specially in the case of thermoplastic composites –TPC–. Therefore, consolidation of thermoplastic composites is becoming one of the most active research topics in composite manufacturing. Many processes proceed by heating prepregs to melt the polymer, then apply a compression in order to remove residual porosity trapped at the layers interfaces and consolidate the material. Thus the different layers containing the molten thermoplastic resin are compressed and squeeze flow occurs. Even if some modeling has been addressed, the flow occurring in the laminate, inside the yarns and in between the yarns requires rich 3D numerical descriptions with a fine enough description of the complex kinematics taking place in the laminate thickness. In this work we analyze the limits of lubrication based descriptions, justifying the necessity of proceeding with 3D descriptions. In order to alleviate the cost that such simulations involve, we employ an advanced discretization technique making use of an efficient in-plane-out-of-plane separated representation of the different fields involved in the model. Thus very fine descriptions are possible with a computational cost characteristic of 2D descriptions, as the ones making use of the lubrication hypotheses.