TOWARDS LOW-COST AND SOLID-STATE AIRCRAFT FOR PLANETARY EXPLORATION
Onur Bilgen, PhD, Department of Mechanical and Aerospace Engineering, Old Dominion University
March 18, 2015, 9:00 am, NIA, Room 101
Abstract:
The aircraft today suffers from a saturation of design space due to the lack of understanding of biological ornithopters such as birds, insects, some mammals, and their unparalleled ability to take off, hover, forage and land in extremely constrained spaces, and travel long distances in varying ambient conditions. Ornithopters achieve all survival functions and more with extreme efficiency which research to date have not been able to fully explain or mimic. The lack of system-level understanding of biological ornithopters has a dual in the engineered world. In man-made aircraft, establishing a wing configuration that is stiff enough to sustain aerodynamic loads, but compliant and tough enough to generate the desired amount of lift and thrust with minimal weight and drag is the central challenge.
Although the reasons not fully understood, one observation can easily be made: The ability to survive observed in biological ornithopters comes from their continuous active and passive physical adaptation to their environment. In contrast, the modern transportation aircraft does precisely the opposite, although the possibility of an aircraft or a control surface to change its shape or to “morph” has interested designers since the beginning of aviation. Shape morphing is almost always observed in nature and results in improved efficiency and control in a wide range of ambient conditions. Unfortunately, to date, almost all morphing concepts resulted in system-level inefficiencies due to the weight associated with the mechanisms to morph the aircraft.
Shape adaptation is a trait that some smart-materials naturally exhibit; hence such materials may offer system-level benefits as actuators for morphing, sensors and energy harvesters while simultaneously improving robustness by reducing the part count and mechanical complexity. This presentation will review recent progress made towards enabling solid-state flight in small unmanned aircraft. Particularly, research in shape morphing of aerodynamic surfaces including static and dynamic camber, thickness and planform control, leading to the flight testing of two small aircraft will be presented. In the applications that will be discussed, coupled analysis of fluid-structure interaction and novel morphing concepts have been employed, and piezoelectric composite actuators were utilized.
Biography:
Dr. Bilgen received his B.S., M.S. and Ph.D. degrees in Mechanical Engineering from Virginia Tech in 2005, 2007 and 2010 respectively, and currently is a tenure-track faculty at the Mechanical and Aerospace Engineering Department of Old Dominion University in Norfolk, Virginia. His technical expertise is in the areas of design, modeling, optimization and experimental characterization of multi-functional, adaptive and composite smart-material structures, morphing aerodynamic surfaces, and small Unmanned Aircraft Systems (UAS). Dr. Bilgen’s research to date in the field of adaptive/active structures, composites and small UAS incorporating smart-materials has led to two book chapters, 26 peer-reviewed journal articles and 40 conference papers, including the ASME / BOEING Best Paper Award at the AIAA SDM 2007 conference, a third place in the BOEING Engineering Student of the Year 2010 Award and an invited plenary session talk at the 5th ECCOMAS Thematic Conference on Smart Structures and Materials. In 2013, Dr. Bilgen was selected as the Most Inspirational Faculty Member of the Batten College of Engineering and Technology at Old Dominion University, nominated by the M.E. student graduating with the highest GPA.