Parametric optimisation of composite shell structures for an aircraft Krueger flap

This paper details the conceptual design optimisation of the configuration and composite lay-ups used to replace the conventional honeycomb stiffened structure of a Krueger flap. The multiple composite laminates selected for redesigning the lay-ups within an initial symmetrical quasi-isotropic ply configuration of [0/45/−45/90]s, had to demonstrate full orthotropic characteristics. In order to construct a numerical process to optimise the required multi-layered composite shells, a commercial finite element code, Ansys, was used to develop a parametric analysis file. This analysis subroutine was then integrated into an Ansys Parametric Design Language code embedding the objective of the optimisation process––mass minimisation––as well as all the constraints and the allowable domains of the parameters. The paper, in its conclusion, presents a comparison between the original product and the optimal design, and reviews the advantages of the future implementation of this design.