Aeroelastic Instability Analysis of a Double-Tapered Composite Wing-Box Using Refined Dynamic Finite Elements

The objective of this paper is to present an investigation into the divergence and flutter analyses of a tapered composite wing, conducted using the normal mode method. A semi-analytical modal analysis method, called Refined Dynamic Finite Elements (RDFE), developed by the lead authors, is presented and compared with the other well established methods, such as exact Dynamic Stiffness Matrix (DSM) and conventional FEM formulations. The wing’s lateral (out of plane) bending and torsional displacements are assumed to be governed by Euler-Bernoulli and St. Venant beam theories, respectively. The thin-walled rectangular closed box-section is assumed to be a Circumferentially Asymmetric Stiffness (CAS) configuration, used to approximate a NACA- 0012-64 wing. To minimize the computing demand in aeroelastic optimization process, an analytical method, developed and used by a number of researchers, is employed to determine the bending, torsion and bending-torsion coupling rigidities of the thin-walled composite wing box structure. The element matrices in the governing equations are established by using the RDFE and the Wittrick-Williams (WW) algorithm is then used to calculate the wing structural frequencies and modes for accuracy and computational efficiency. The aeroelastic analysis of the composite wing model, subjected to quasi-steady incompressible aerodynamic flow, is then carried out to investigate the maximum flutter and divergence speeds.

کلیدواژه ها:

Double-tapered composite wing box ، coupled bending-torsion vibrations ، geometriccoupling ، material coupling ، aeroelastic instability ، FEM ، Dynamic Finite Element (DFE)