Abstract
This paper presents a Ritz method for conducting flutter analysis of a NASA X-57 Maxwell-like distributed propulsion aircraft wing. The Jacobi polynomials are used to approximate the bending displacement and torsion angle in the flutter analysis, which enables efficient evaluations of structural and aeroelastic responses of a distributed propulsion wing under different design parameters. Compared to the simple polynomials, Jacobi polynomials can eliminate the well-known ill-conditioning numerical issues when considering higher orders of polynomials in the Ritz method. Additionally, the weight functions can be easily modified along with the Jacobi polynomials to satisfy different boundary conditions without loss of orthogonality. Research study shows that the mode shapes approximated using the Jacobi polynomials and weight function are very similar like the analytical mode shapes for uniform and straight wings. To verify and demonstrate the efficiency of Jacobi-Ritz method-based aircraft wing flutter analysis, simple polynomials and uniform wing’s analytical mode shapes based trial functions are also studied in the Ritz method based flutter analysis. The influence of distributed propulsor mass, nonuniform aerodynamic model for the wing with multiple propulsors and the sweep angle on the flutter speed are studied and discussed.
