Paper number 495

DESIGN AND OPTIMISATION OF COMPOSITE PLATES WITH CUTOUTS

Rodney S. Thomson¹ and Murray L. Scott²

1Cooperative Research Centre for Advanced Composite Structures Limited, 506 Lorimer Street, Fishermens Bend, Victoria, 3207, Australia.
2The Sir Lawrence Wackett Centre for Aerospace Design Technology, Department of Aerospace Engineering, Royal Melbourne Institute of Technology, GPO Box 2476V, Melbourne, Victoria, 3001, Australia.

Summary

The optimisation of cutouts in laminated composite plates under a variety of loading conditions has been investigated using the design sensitivity method of MSC/NASTRAN. Two approaches were investigated: optimisation of the cutout shape and optimisation of local cutout reinforcement. For the shape optimisation, a least squares objective function was shown to successfully produce a constant failure index around the hole boundary under biaxial loading. The shape optimisation of holes in laminated composite plates showed that the optimum shape depends on the degree of orthotropy. Quasi-isotropic laminates produced holes of similar shape to the isotropic case while laminates without fibres in the primary loading direction could produce unexpected shapes. A minimum weight objective was used to introduce local hole reinforcement which reduced the failure index in the panel to that of a panel without a hole. Significant weight savings were demonstrated.

Keywords

design, optimisation, cutouts, neutral holes, finite element method.