Author(s)

DOGAN COK, FAZIL O. SONMEZ

Abstract

This study develops a methodology for optimally designing composite I-beam wing spars with a wavy corrugated web under aerodynamic loads to minimize mass. Using the Hurkus Advanced Training Plane as a reference, the lift forces calculated from aircraft mass are applied directly to the spar as a transverse load. IM7/8552 carbon-fibre reinforced composite is selected for its high strength-to-weight ratio. Given that web buckling under shear is the critical failure mode, a buckling analysis determines the failure load. Codes are developed using ANSYS Parametric Design Language to implement the optimization algorithm and carry out structural analyses to determine the load capacity of the spar. The web is modelled as a multi-period wave defined by four parameters (initial wavelength, wavelength increment rate, initial amplitude and final amplitude). The objective is to minimize spar mass subject to buckling constraint. The modified simulated annealing algorithm – a stochastic global search method – identifies the optimal web shape. Results show a significant mass reduction while maintaining adequate strength compared to conventional spars.

Keywords

wing spar design, fibre composites, nonlinear buckling, structural optimization, finite element analysis (FEA)