Distributed Strain Sensing for the Integrated Adaptive Wing Technology Maturation Wind Tunnel Model

Among the numerous aeroelastic considerations for high aspect ratio wings, optimizing aerodynamic performance, managing aerodynamic loads, and avoiding dynamic instabilities at off-design conditions are essential. Addressing these issues using active controls, rather than increased stiffness and weight, is one of the key objectives for the Integrated Adaptive Wing Technology Maturation (IAWTM) project. Based on the NASA Common Research Model, modified to have an aspect ratio of 13.5, the IAWTM semispan wind tunnel model will have 10 control surfaces located on the trailing edge to be used for drag optimization, maneuver and gust load alleviation, and flutter suppression. In addition to traditional point transducers, the model will also be instrumented with fiber optic sensors for distributed strain measurements. Advances in sensor performance have led these fiber optic strain sensors to be an enabling technology for real-time, lightweight, distributed sensing for structural analysis and feedback control of flexible systems. Since fiber optic strain sensors will be used in the IAWTM multi-objective controllers, several risk-reduction activities have been planned and conducted to develop tools and techniques for their incorporation into the wind tunnel control architecture. These tests include benchtop shape sensing experiments on beams and plates as well as plans for flexible wing testing in a low-speed wind tunnel. The efforts described here will support the quasistatic shape control and model suppression objectives of the IAWTM project.