Flutter prediction, suppression and control in aircraft composite wings as a design prerequisite: a survey

Abstract

Emergence of flutter compromises not only the long‐term durability of the wing structure, but also the operational safety, flight performance and energy efficiency of the aircraft. Effectual means of flutter prevention are, therefore, mandatory in the certification of new flight vehicles. This work intends to address the flutter phenomenon highlighting the above issues, and reviews some of the most recent theoretical and experimental developments in flutter analyses. In the following subsections, theoretical, computational and experimental flutter for composite structures is pursued. In particular, panel flutter, thrust‐induced flutter, wing/store‐type flutter, non‐linear flutter, damaged panel flutter, flutter in compressed flow and flutter control via neural networks are covered. Effects of fibre/ply orientation on flutter are also briefly covered. The review further looks into aerothermoelastic behaviour of composite structures buckling problem and hopf bifurcation point determination. Analysed flutter of actively/passively controlled composite structures is critically reviewed due to the emphasized importance in modern structures. It is appreciable that the knowledge gained from the study of flexible structures and unsteady airflows in aircraft can be transitioned back to more traditional flutter studies. It is hoped that this review work will stimulate research and collaborations that will lead to significant progress in the understanding of this dynamically rich and potentially important area of enhancement of flutter prediction, suppression and control of active and passive composite aircraft structures. Copyright © 2006 John Wiley & Sons, Ltd.

A novel dry powder inhaler: Effect of device design on dispersion performance

“…As described above, increases in turbulence may affect flutter dynamics (onset and intensity), hence, will affect drug dispersion performance. However the nature of flutter dynamics and its relationship with the device geometry and dimensions are yet to be fully understood in our case and even in well developed areas of flutter research due to the complexity of the interactions between the air flow and the dynamic structure undergoing flutter (Meirovitch and Ghosh, 1987;Njuguna, 2007).…”

“…Flutter occurs when the fluid surrounding a structure feeds back dynamic energy into the structure instead of absorbing it, greatly intensifying the energy within the structure (Gallegos, 2008). Flow induced flutter has been studied intensively as a detrimental phenomena in examples such as airplane wing design and bridge construction (Njuguna, 2007;Meirovitch and Ghosh, 1987). In our previous studies, laser vibrometry was employed to assess flutter dynamics (frequency and acceleration) of aeroelastic films in a prototype inhaler (Gallegos, 2008;.…”

Optimization of Shunted Piezoelectric Patches for Vibration Reduction of Complex Structures: Application to a Turbojet Fan Blade

“…Les applications concernent, en grande majorité, la réduction des phénomènes de flottement, que cela soit en actif [114,87,124] ou semi-passif/passif [37,9]. Elles portent sur le contrôle de pâle d'hélico-ptère, d'aile [94], d'aileron [114], de volet [124] ou d'une partie d'un fuselage.…”

Flutter Control of a Lifting Surface via Visco-Hysteretic Vibration Absorbers

“…Such stores can reduce the flutter speed and thereby degrade the operational and mission effectiveness of combat airplanes. Due to the importance of flutter avoidance, considerable research has been conducted in the last decades to develop and assess the capabilities of various flutter control concepts (Marzocca et al, 2002;Njuguna, 2007). In the general context of studies on semi-active/active methodologies, an important aspect is associated with the spatial optimization of actuator and sensor parameters to facilitate control of targeted modes while providing roll-off of higher-order modes without the need for phase-inducing filters.…”