Numerical modelling of damage development and viscoplasticity in metal matrix composites

Metal matrix composites can exhibit inelastic response due to matrix viscoplasticity as well as fiber/matrix interfacial damage. This paper presents a numerical procedure that can be used to implement a micromechanical model based on a periodic array of continuous fibers embedded in a metallic matrix. The model incorporates elastic-viscoplastic constitutive equations for the matrix and non-linear interfacial traction-displacement relations for the fiber/matrix interface. Generalized plane strain finite elements are formulated in such a way to allow the application of multiaxial loadings while only having to discretize a generic transverse plane. Non-linear lamination theory provides the link between the micro- and macro-level responses of laminated composites subjected to thermomechanical loading. Numerical results indicate that a relatively small number of elements are required to achieve mesh convergence. Also, the axial tensile response is independent of the condition of the fiber/matrix interface, while debonding significantly influences the transverse tensile and axial shear responses.