Numerical modelling of single-curvature composite materials sheet-forming

A plane strain finite element model is developed which can model isothermal shearing and plane transverse flows encountered in forming thermoplastic or thermoset continuous fiber composite laminates into single-curvature shapes. These flows are the dominant mechanisms in the forming of important industrial shapes such as J- and U-beams for aerospace applications. Each composite ply is assumed to behave as a transversely isotropic incompressible Newtonian fluid with a single fiber direction in which the fluid is inextensible. The finite element formulation uses a mixed penalty approach with independent interpolation of the velocity, pressure and fiber tension stress fields. Results are shown which agree well with available analytical studies for both single-ply and multi-ply deformations. Experimental characterizations of the interply slip behavior are used to develop a general purpose contact-friction algorithm for forming situations. The results shown are an important step towards the development of a simulation tool for single-curvature composite forming.