Chapter 1: Correlation of structural strain to tip vorticity and lift for a MAV pliant membrane wing

Abstract

The last decade has witnessed a surge of scientific interest in flight at the micro air vehicle (MAV) scale. To date, a MAV utilizing an adaptable, flexible smart wing design has yet to come to fruition. While highly flexible aerodynamic surfaces have repeatedly demonstrated improved performance through passive adaptation, limited structural and flow state knowledge prevents the inclusion of active control strategies which could improve performance of such designs. In this work, a flexible membrane wing constructed of latex was considered. The goal of estimating lift was approached through experimental and theoretical correlation of wing strain state due to flow-induced pressure. Using visual image correlation, elastic deformations, strains and membrane pretensions of the wing were measured in the Oregon State University wind tunnel. In addition, a six-degree-of-freedom sting balance was used to determine aerodynamic loads. A linear membrane wing formulation was utilized to correlate the wing's structural strain to lift and wing-tip vorticity. Results of the forces measured by a sting balance were then compared to those predicted by flow simulation. This work describes experimental results that illustrate the effectiveness of low fidelity models in predicting and estimating useful information for flexible wing designs. © The Society for Experimental Mechanics, Inc. 2013.