Dr. David E. Alexander
- Associate Scientist (retired)
My general area of interest is biomechanics, which uses engineering techniques and approaches to study the physical properties of organisms, and the interactions between organisms and their physical environment.
I am particularly interested in studying ways in which flying animals achieve similar results to airplanes, using fundamentally different mechanisms, such as for maneuvering or lift augmentation. For example, I have used high speed cinematography to study wing movements that produce turns by flying dragonflies. Students in my lab are investigating aerodynamic effects of wing architecture and stabilizing mechanisms of flying insects.
Analytical methods for studying flight stability in airplanes are not easily applied to animals, so we have developed empirical methods to measure stability, and in addition to flight stability we have studied stability in crustacean swimming. We have also developed techniques to measure the mechanical properties of very small structures, and students have used these techniques to study the stiffness of swimming appendages in small crustaceans and cuticle strength in caterpillars.
I have also studied arthropod swimming mechanics and energetics. These studies include experiments using high speed cinematography and force measurements, fluid mechanical analyses and computer modeling, and gas exchange measurements and energetic analyses. These studies will help answer such questions as: What are the mechanical and physiological constraints on swimming arthropods? What arthropod swimming modes are most efficient, and how do they compare to other swimming animals?
Selected Publications —
Alexander, D. E. (2015). On the Wing: Insects, Pterosaurs, Birds, Bats and The Evolution of Animal Flight. ISBN: 978-0-19-999677-3.