Energy Harvesting From Aeroelastic Instabilities for Highly Flexible Aircraft

Abstract

Aeroelastic instabilities such as flutter, limit cycle oscillation (LCO), and divergence are traditionally considered undesirable. Designers try to avoid these instabilities by adding enough stiffness or damping to structures. A new approach to suppressing these instabilities is to use smart material to harvest energy from airflow. In this way not only are the aeroelastic instabilities avoided, but also some energy will be harvested. The harvested energy can be used for powering sensors, morphing parts of the structure, and ultimately increasing the performance of the aircraft. Energy harvesting from aeroelastic phenomena can also be used in designing small wind energy harvesters for home use. In this paper we will explore both capabilities. Piezoelectric materials are among the attractive smart materials for energy harvesting. Piezoelectric materials generate electric potential as they deform. We will explore the use of these materials in aeroelastic harvesting. Ref. 1 has a general overview of different forms of vibrational energy harvesting, including the use of piezoelectric materials. Harvesting energy from aeroelastic instabilities is a relatively new area; therefore, the body of literature on this subject is relatively young. Most of the analysis is limited to a 2-D cross-sectional analysis with steady or quasi-steady flow. We will use a 2-D model with an unsteady aerodynamic model as the preliminary result. More realistic cases with a beam model will be added to the final version of the paper. For the beam model, we will use fully intrinsic equations.