A new viscoplastic model and experimental characterization for thermosetting resins

Resins as matrix materials for structural composites show nonlinear rate-dependent mechanical behaviors. In the present work, a new viscoplastic constitutive equation based on a potential function is proposed to predict the mechanical response of an epoxy matrix to any three-dimensional loading condition. The proposed potential function is a combination of the second and third invariants of the deviatoric stress tensor as well as the first...