Viscoelastic bending model for continuous fiber-reinforced thermoplastic composites in melt

Bending of single plies or stacks of multiple plies is an essential deformation mechanism during thermoforming of thermoplastic composites. A reliable prediction of the forming process requires an accurate description of the bending behavior. To this end, a characterization method for the bending of composites under thermoforming conditions has been developed. Experiments are performed with an in-house developed bending setup and are analyzed with an analytical model, which is derived in this paper. The model describes the composite with linear elastic fibers and a matrix material that behaves as a shear thinning power law fluid. The model can represent the characteristic behavior that is measured in bending experiments with unidirectional carbon fiber reinforced PA6 composites.