Inverse Identification of In‐Plane and Out‐Of‐Plane Behavior of High‐Performance Unidirectional Thermoplastic Composites in the Molten State

ABSTRACT A computational methodology for identifying the viscoelastic material parameters for thermoplastic unidirectional (UD) composites from bending and in‐plane shear tests in molten state is presented, using a hypo‐viscoelastic constitutive model. The key innovation lies in the numerical identification of in‐plane and out‐of‐plane material parameters from experimental data (bias extension and bending tests) through a reverse engineering approach employing an optimization algorithm and finite element (FE) simulations. The identified material parameters successfully reproduce the experimental bending and bias extension response for different loading rates.