The buckling response of carbon fibre composite panels with reinforced cut-outs

This paper investigates the influence of cut-out diameter and reinforcement type upon the buckling stability of square CFRP panels. The study undertaken at Cranfield University in GB uses NASTRAN Finite Element Analysis (FEA) extensively for this investigation. The FEA results have been compared with results from practical tests and good agreement was found. Diagrams showing the influence of cut-out diameter, reinforcement lay up and thickness on the buckling stability of clamped or simply supported CFRP panels are presented. The results are shown for 2 mm thick ((± 45/0)_s)_s square CFRP panels with 30 mm wide reinforcement rings bonded around the central circular cut-outs. The panels are loaded in pure shear or in compression. The effect of reinforcement rings bonded to one or both sides of the panel has been investigated and shown in diagrams. The results presented can be used to find the optimum reinforcement type and thickness for square CFRP panels with central circular cut-outs.