Event Location: NSH 1507

Abstract: Prior experimental data has indicated that flying animals operate at
safety factors much greater than those generally used in manufactured
flying vehicles. However, comparative data on the range of structural
strengths represented by living flyers, and their correlations with
specific modes of movement, are considerably less common in the
literature. Flying animals may provide insights for robotic design,
especially with regards to micro air vehicles, but also for any systems
designed to move in unpredictable environments with strict weight
requirements. Birds, bats, and pterosaurs all demonstrate a wide array of
adaptations related to maintaining structural integrity in unpredictable
environments. In this talk, I will present the results of my recent work
on the skeletal rigidity in the wings and hind limbs of a wide range of
flying species. I place special emphasis on pterosaurs, which have often
been overlooked in biomechanical analyses because they have no living
representatives. Despite being an enigmatic fossil group, pterosaurs
provide numerous insights regarding weight distribution, passive load
accommodation, and multi-purpose limb systems. Pterosaurs are especially
informative for understanding the size limits of flapping flyers (as in
the construction of ornithopters), as they included the largest known
flying animals. I will supply evidence that pterosaur forelimbs acted as
a multi-purpose module, supplying both aerodynamic force in flight and
acting as a primary launching module, by supplying leaping force, when
entering flight from the ground. I will further demonstrate that failure
loads in the forelimb of living birds encompass a nearly seven-fold range,
while bats are considerably more constrained, and utilize less rigid wing
skeletons. Finally, adaptations to outboard stall reduction and gust
alleviation will be considered.