Computationally Efficient Buckling Analysis of Damaged Composite Sandwich Panels in Wind Turbine Blades

Major parts of a wind turbine rotor blade are designed as sandwich panels, which consist of thin face sheets and a thick sandwich core. The face sheets are normally made of glass fiber reinforced polymer (FRP) laminates while the sandwich core usually consists of polymeric foams or balsa wood, depending on the blade design and the position along the blade. The buckling resistance of these sandwich panels is of importance in the design analysis of the ultimate limit state. Additional complexity in this analysis arises from local damages, e.g., delamination or matrix cracks, curved geometries, material inhomogeneities or other discontinuities within the panel. These local imperfections can have a major influence on the buckling behavior. A practical approach to predict the global buckling response and local effects of arbitrary sandwich panels with local damages or discontinuities is the finite element analysis