Optimum wing shaping and gust load alleviation of highly flexible aircraft with finite actuations

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University of Alabama Libraries

The idea of improved flight performance is a constant goal within the aircraft design industry. In order to have aircraft which can fly further and for longer durations improved aerodynamic efficiency is required. Traditionally this is achieved through the use of discrete control elements such as flaps and slats. These mechanisms have a useful purpose in instances such as take off and landing, but are not often useful in other flight conditions because they tend to generate large amounts of drag. Recent research has shown that the potential for a continuously deformable wing is desired to effectively improve flight performance at any given flight condition. One example of this technology is NASA's Variable Camber Continuous Trailing Edge Flap (VCCTEF) which creates a trailing edge for an aircraft wing which can change the camber of individual sections without creating any discontinuities which generate drag. This application deals with small scale deformations (camber change) which can be improved to dealing with large scale deformations (bending, torsion, etc.) through the use of flexible structures and actuator systems. The first step in utilizing these large scale deformations to improve flight performance is to determine what wing geometries produce the most efficient performance. One method of determining this is to utilize an aeroelastic optimization process to define the wing geometry. Exploration of this optimization requires a definition of improved flight performance. The work expressed within this project used a reduction in drag as a measure of improved flight performance. This was chosen because if one considers an electric aircraft its range and endurance can be improved by reducing the drag experienced by the aircraft. The optimization was further improved when additional objectives were considered. The control cost required for these geometries gave insight into how much energy is required to gain the energy savings by increasing efficiency. Additionally some wing geometries were shown to produce better results at reducing the effects of wind gusts. After these optimizations were defined, an additional optimization was constructed to determine the best placement and number of actuators used to generate these wing geometries. Moving forward, the optimization will be applied over a range of velocities which will be used to develop a linear parameter varying controller. This controller will be designed to seamlessly transition between the optimum wing geometries at varying flight conditions.

Electronic Thesis or Dissertation
Aerospace engineering