Modeling of composite laminates with multiple delaminations under compressive loading

Multiple delaminations are more realistic damage types in the laminated composite structures. In this study, buckling and postbuckling analysis was conducted for the composite laminates with multiple delaminations under compressive loading. In a nonlinear finite element formulation, the updated Lagrangian description and modified arc-length method were adopted. For a finite element modeling of composite laminates, the eight-node degenerated shell element was used. To avoid the overlapping between delaminated layers, which is a physically inadmissible buckling mode, the contact node pair was defined by use of virtual beam element. It employed constraints at the overlapped region in the load incremental procedure. Using this modeling of multiple delaminations, accurate results were obtained for the buckling and postbuckling behavior of composite laminates. Numerical results showed that multiple delaminations lower buckling loads and load carrying capacities in the postbuckling region.