Session: 02-01-01: Aero-, Servo-, Thermo-Elasticity of Aircraft, Rotorcraft and Spacecraft

Paper Number: 152407

152407 - Effect of Nonlinear Energy Sink on Aeroelasticity of High Aspect Ratio Wings 

Classical flutter instability is an aeroelastic interaction occurring due to the coupling of bending and torsion motions of the structure. This problem can occur in aircraft wings, control surfaces and helicopter blades. Flutter induces cyclical loading which in turn serves to vastly reduce the fatigue life of components and can cause catastrophic failure [1, 2]. The current push for higher aspect ratios in civil aviation means the severity of flutter induced vibration is increased and, for this reason, flow control mechanisms and vibration reduction techniques are being investigated for mitigating against flutter instability [3]. Conventional linear damping devices have been well documented however the effectiveness of nonlinear absorbers regarding this problem has not been investigated for wings undergoing moderate/large deflections [4]. For this reason, this paper integrates a Nonlinear Energy Sink (NES) into a numerical model of a high aspect ratio wing in flutter to assess the vibration reduction achievable with a nonlinear device. These devices have shown to be effective when applied to 2D aerofoil models in previous works [5, 6], therefore the expansion to high aspect ratio wings is a novel step with promise. The structural dynamics of the wing is modelled using an equivalent beam formulation which is an adapted form of nonlinear beam theory presented by Crespo da Silva and Glynn [7] and is discretised using Galerkin’s method as presented in [8]. The aerodynamic forces are modelled using a combination of Wagner’s indicial lift model, to simulate the attached unsteady flow, and strip theory to integrate the lift and moment across the span, as was demonstrated in [11]. The Nonlinear Energy Sink (NES) attachments are fitted as in-wing shock absorbers.

Presenting Author: Ira Wall University of Nottingham

Presenting Author Biography: Ira is a final year PhD student from the University of Nottingham. In 2022 he completed his MEng in Aerospace Engineering at Nottingham and decided to pursue further research. Currently his research is focussed on nonlinear dynamics and vibration reduction with a specific focus on damping devices for high aspect ratio aerostructures. The paper he is presenting investigates the effectiveness of a Nonlinear Energy Sink (NES) at reducing limit cycle oscillations of an aircraft wing undergoing flutter instability.