Crack-Induced Effects on Aeroelasticity of an Unswept Composite Wing

Abstract

Crack-induced changes in the aeroelastic boundaries of an unswept composite wing are investigated. The bending-torsion couplings due to the unbalanced laminates and offset of the center of gravity are incorporated into the equation of motion. The edge crack, modeled with the local flexibility concept, introduces additional boundary conditions at the crack location. The fundamental modes of the intact and cracked beam are used in Galerkin's method, and the approximate solution for flutter and divergence speeds is obtained with steady and quasi-steady aerodynamic forces applied. Changes in flutter and divergence speeds (with respect to the crack ratio and its location, along with the fiber orientation) are compared. In many cases, the existence of an edge crack imposes detrimental effects on the aeroelastic boundaries, although it may increase the flutter and/or divergence speed when fibers are orientated at certain angles. The results may help composite wing designers in their aeroelastic tailoring and structural engineers in designing damage prognosis tools to predict the health status of, composite wing structures.