Unmanned aerial vehicles are a class of aircraft that operate without a human pilot on board and applicable in a lot of areas including weather condition monitoring, surveillance, and reconnaissance. Wings are the major area of interest to analyze the maneuverability of an unmanned aerial vehicle. They need further development in design, especially, for the turbulent atmospheric conditions because wind gusts create an abrupt atmospheric situation for unmanned aerial vehicles during the flight. One of the promising ways to reduce the effects of the gust is by using smart materials for the wings. Among the smart materials, dielectric elastomer membranes are electroactive polymers characterized by a large change in the strain as a response to electrical stimulation and found suitable for gust alleviation. They are composed of thin elastomer film sandwiched between two compliant electrodes. The elastomer is incompressible, it squeezes in thickness and extends in the in-plane direction due to the electrostatic pressure created by the applied voltage and regains its original shape after the withdrawal of voltage. This outlines a variation of the tension in the wing that can be used to change its dynamic behavior. In this study, a wing specimen of an electroactive membrane, VHB 4910 is considered and a conductive material, carbon grease is used as the electrode material on both surfaces. A brief increase in the wind speed for a small period is called wind gust. Gust models are generated to explain atmospheric turbulence and turbulent winds in the storm. In this study, a continuous gust profile and two types of stochastic gust models, i.e., the Dryden and the von Karman gust models are developed to study the effects of gust load on the flexible membrane wing. A fluid-structure interaction model containing the finite element model of the membrane and computational fluid dynamics model of the surrounding air flow is created. Aerodynamic coefficients are calculated from the forces found from the numerical results for different gust velocities. A wind-tunnel experimental setup is used to investigate the aerodynamic responses of the membrane wing. The Dryden and the von Karman gust models are found comparable with a minimum variation of magnitude in the gust velocity profile. The coefficients of lift and drag fluctuate significantly with the change in velocity due to wind gust. The validation of the fluid-structure interaction model is performed by comparing the numerical results for the coefficient of lift with the experimental results. The outcome of this study contributes to better understand the aerodynamics and maneuverability of unmanned aerial vehicles in the gust environment.


Fluid-Structural Dynamic Characterization of a Membrane Wing in a Gust Environment

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

IMECE2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.