Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Fluid-structure interaction analysis of a flexible wing using the lifting-line theory and the Euler-Bernoulli beam model via a finite element approach
Submission Author:
Murilo Caetano da Silva , SP
Co-Authors:
Murilo Caetano da Silva, Felipe Liorbano, Ricardo Afonso Angélico
Presenter: Murilo Caetano da Silva
doi://10.26678/ABCM.COBEM2021.COB2021-0558
Abstract
In the aviation sector, there is a concern over developing new aircraft technologies that are more eco-friendly. Among the advances, the increase of wing aspect-ratio in commercial aircraft and the incorporation of composite materials may lead to slender structures contributing to weight and drag reduction. Furthermore, it also provides aerodynamic surfaces that exhibit higher structural flexibility. This emphasizes the importance of the coupling between aerodynamic and structural models into an aeroelastic one. One of the approaches consists of using a lifting-line based aerodynamic model and an Euler-Bernoulli structural model. Hence, this article aims to develop an aeroelastic model based on the ones mentioned above using a finite element approach for both domains, viz. aerodynamic and structural. The discretization of both problems with the same numeric approach allows describing the circulation and the displacement fields with a polynomial basis. The routines relative to each model were developed separately and implemented in Python using the object-oriented paradigm. An existing Python code implemented to predict the aerodynamic response of finite wings through the Finite Element Method - previously validated - was modified to compute the nodal forces. These will be used in the structural code to calculate displacements and rotations. On the other hand, structural displacements affect the wing aerodynamic behavior, producing new forces and moments that will deform the structure again. This iterative process continues until it reaches a specified tolerance concerning aerodynamic and structural degrees of freedom increments. A fixed-point algorithm is used for the iterative process. The techniques mentioned above allow obtaining an interaction between the domains without interpolations, which can be interesting for dynamic analysis. In the end, the developed code will be validated by comparison with available literature data. The implemented model comprises a rectangular wing with span b = 9.144 m, chord c = 0.3048 m, airfoil NACA 0012 with a lift curve slope of a0 = 6.382 rad−1. The aerodynamic load is applied directly to the wing spar, which has an I-shape (Ixx = 716.1 × 10−9 m4, S = 3.952 × 10−3 m2), manufactured in 6061 aluminum alloy (E = 68.95 GP a). Regarding the flight condition, the speed is U∞ = 91.44 m/s and the wing is analyzed for an angle of attack of α = 6.89◦. The proposed model was compared with literature data and exhibits a maximum wingtip displacement difference of 0.06% of the wing semispan.
Keywords
fluid-structure interaction, lifting-line theory, Beam theory, Finite Element Method, load distribution
