Experimental and numerical investigations of compression stability of stiffened composite panel with ply interleaving

A novel composite layup technique (ply interleaving) is proposed to satisfy the extraordinary needs in aircraft structure design. Buckling experiments and corresponding simulations with different configurations are carried out to study the mechanical properties of the stiffened panel with this ply layout and get a suitable numerical prediction method. A ply-by-ply-based modeling technique is applied to characterize the real discontinuity in each ply. Additionally, the relationship between the macroscopic buckling and damage evolution is investigated by the comparative analyses of experiments and simulations. The investigations show the following results: the panel with ply interleaving has a considerable anti-buckling capability besides its flexible layout; both adhesive layer damage and lamina damage should be included in the simulation for obtaining reliable solution; the panel would buckle while adhesive layer damage occurs between stiffeners and skin, which initiates firstly in the ply interleaving zone and then expands to the surrounding area; internal damage of each ply also originates around discontinuities then develops rapidly, leading to the panel failure. The prediction results of buckling and failure show good agreements with the experimental results, so the suggested simulation technique is verified to be an effective method to study the mechanical behavior of the composite plate with preset discontinuities.