In-Flight Wing-Membrane Strain Measurements on Bats

  • Roberto Albertani
  • Tatjana Hubel
  • Sharon M. Swartz
  • Kenneth S. Breuer
  • Johnny Evers
Conference paper
Part of the Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)


An efficient system for high-resolution measurements of a bat wing’s membrane during flight is presented, proving the feasibility of dynamic strain measurements on bats wing membranes during flapping. Data were collected from wind tunnel wind-off flights of a Jamaican fruit bat, Artibeus jamaicensis, a nocturnal and frugivorous specie trained by Brown University team to fly back and forth in the test section. Visual image correlation was used for image post-processing providing spatial highresolution three-dimensional displacements and strains on the bat’s wing.

Temporal membrane surface-averaged strain analysis showed a level of strain in the X direction (spanwise) approximately three times larger then the Y direction (chordwise) with values around 10% and 3%, respectively. Strains are estimated from an unknown reference state at the beginning of each recorded sequence. Full surface membrane strain distribution shows a consistent strain-relief effect around the ring finger during downstroke in the X direction (spanwise). Temporal wing section shape analysis during a down stroke revealed a higher camber and a significant pitch-up twist of the ring finger respect to the free membrane between the little and ring finger.


Wind Tunnel Test Section Ring Finger Wing Membrane Frugivorous Species 
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Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Roberto Albertani
    • 1
  • Tatjana Hubel
    • 2
  • Sharon M. Swartz
    • 3
  • Kenneth S. Breuer
    • 2
  • Johnny Evers
    • 4
  1. 1.Research & Engineering Education Facility (REEF), Department of Mechanical and Aerospace EngineeringUniversity of FloridaShalimarUSA
  2. 2.Division of EngineeringBrown UniversityProvidenceUSA
  3. 3.Department of Ecology and Evolutionary BiologyBrown UniversityProvidenceUSA
  4. 4.Air Force Research Laboratory, RWGNEglin AFBUSA

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