A semi-analytical approach for flutter analysis of a high-aspect-ratio wing

Abstract

We present a hybrid, semi-analytical approach to perform an eigenvalue-based flutter analysis of an Unmanned Aerial Vehicle (UAV) wing. The wing has a modern design that integrates metal and composite structures. The stiffness and natural frequency of the wing are calculated using a Finite Element (FE) model. The modal parameters are extracted by applying a recursive technique to the Lanczos method in the FE model. Subsequently, the modal parameters are used to evaluate the flutter boundaries in an analytical model based on the p-method. Two-degree-of-freedom bending and torsional flutter equations derived using Lagrange’s principle are transformed into an eigenvalue problem. The eigenvalue framework is used to evaluate the stability characteristics of the wing under various flight conditions. An extension of this eigenvalue framework is applied to determine the stability boundaries and corresponding critical flutter parameters at a range of altitudes. The stability characteristics and critical flutter speeds are also evaluated through computational analysis of a reduced-order model of the wing in NX Nastran using the k- and pk-methods. The results of the analytical and computational methods are found to show good agreement with each other. A parametric study is also carried out to analyse the effects of the structural member thickness on the wing flutter speeds. The results suggest that changing the spar thickness contributes most significantly to the flutter speeds, whereas increasing the rib thickness decreases the flutter speed at high thickness values.

On the multi-fidelity approach in surrogate-based multidisciplinary design optimisation of high-aspect-ratio wing aircraft

“…Low-fidelity aero-structural models are also extensively used in flutter speed calculations. Examples of two and three-dimensional low-order models used for flutter boundary calculations based on small unsteady disturbances about a known steady flow CFD solution can be found in Opgenoord et al [31] or Latif et al [32]. In Opgenoord et al [33] a comparison of analytical methods for flutter and post flutter calculations in a wing section with three degrees of freedom is presented and a hybrid approach involving analytical and Finite Element models for flutter calculations is presented in Sudha et al [34].…”

Aplicação de transdutores piezoelétricos para o controle da instabilidade de whirl-flutter

“…Tal instabilidade pode ser entendida de uma forma geral como um fenômeno aeroelástico dinâmico no qual forças aerodinâmicas, elásticas e inerciais interagem em uma asa fixa ou rotativa. Tal interação faz com que a energia provida pelo fluido seja rapidamente absorvida e transformada em vibrações mecânicas que resultam em uma resposta vibracional divergente [6]. Se a velocidade do escoamento for aumentada, pode haver uma determinada velocidade crítica denominada de velocidade de flutter.…”

Parametric Modeling of a Long-Range Aircraft under Consideration of Engine-Wing Integration

“…More recently, Latif et al [7] presented a semi-analytical approach to perform flutter analysis of a high-aspect-ratio wing modeled as a cantilevered beam. Although the investigated configuration is an Unmanned Aerial Vehicle (UAV) without a wing-mounted engine, this study, furthermore, neglected the stiffness of the wing-fuselage attachment and does not capture the flutter responses of the tail planes as a wing-alone configuration was investigated.…”