A Multiscale Progressive Damage Analysis for Laminated Composite Structures using the Parametric HFGMC Micromechanics

A nonlinear multiscale damage analysis framework, which is based on the parametric High Fidelity Generalized Method of Cells (HFGMC) micromechanics, is developed to predict the mechanical response of laminated composite structures, with and without notches, subjected to tensile and compressive static loading. A refined hexagonal-array repeating unit-cell (RUC) HFGMC micromodel for the unidrectional composite microstructure is discretized into subcells to represent explicity the fiber and matrix phases at the microscale level. The material behaviors of the fiber and matrix constituents, are directly prescribed. The fiber is considered to behave as an elastic transversely isotropic material. The nonlinear material for the matrix phase is represented by the J2-deformation plasticity theory. The predicted HFGMC overall in-plane shear and longitudinal moduli of a single composite lamina together with a compressive strength equation are applied to determine the micro-buckling compression failure of a lamina. To determine the failure of an individual composite lamina due to the fiber, matrix, or in-plane shear failure modes, the local strain field within each subcell within the RUC in conjunction with the strain invariant failure theory (SIFT) criterion are employed. Once failure is detected within a subcell, the (cell-extinction-damage) CED damage modeling approach is employed to remove the considered subcell from the hexagonal RUC. This framework is implemented as a user material subroutine within standard displacement layered-shell FE models of laminated composites. When failure of RUC representing an individual layer is determined, the corresponding material point is removed from the thickness at the global surface integration point of the shell finite element. The properties and damage parameters of the composite constituents are determined by proper calibration of the axial, transverse, and in-plane shear responses of unnoteched laminates. Damage analyses for both un-notched and notched laminated structures are presented and compared with available experimental results