Numerical Flutter Analysis of Flexible Wings: A Unified Cross-Sectional Properties, 3D Beam Modal Analysis, and SDPM Integration Integration internship

Abstract

Reliable prediction of classical bending–torsion flutter in flexible finite wings is addressed within a transparent and reproducible numerical environment. A computational framework was established that integrates spanwise cross-sectional properties from mesh-based sectional analysis, a three-dimensional Timoshenko-beam finite-element model to obtain wind-off natural frequencies and mass-normalised mode shapes, and the frequency-domain unsteady lifting-surface formulation of the SDPMflut software. Mode shapes were reconstructed on a chordwise–spanwise grid to enable aerodynamic coupling, and the coupled complex eigenproblem was solved across airspeed. Consistency with available experimental references was demonstrated on a ULiège laboratory wing reconstructed from a high-fidelity dataset, where the predicted modal patterns and the evolution of frequency and damping with airspeed reproduced the expected behaviour when equivalent modelling choices were adopted. Discretisation studies indicated mesh-independent aeroelastic indicators beyond moderate structural and aerodynamic resolutions. Parameter-wise envelopes quantified the sensitivity to mass, stiffness, damping targets and Mach number. The frequency-placement metric χ = f_h/f_α efficiently summarised the relative ordering of bending and torsion branches. Within the stated assumptions, the computational framework provided traceable data exchange with the SDPMflut software, credible convergence evidence, and practical uncertainty bounds that support early aeroelastic risk screening and post-test interpretation.