Project Report

This research contributed knowledge about the tensile strength, Young's modulus, and visco-elastic properties of bat wing skin. This describes how the material that makes up the bat wings responds to external forces such as the wind or the impact of insects. As the force affects the wing membrane, it will stretch and break differently depending on wing location and direction of the force. The uropatagium showed the greatest stiffness among the wing regions. The wing has small features called corrugetions that can be seen when the wing is placed over a bright light. When the wing membrane is tested perpendicular to corrugations, the modulus is much higher compared to when it is tested parallel to corrugations. The modulus describes how easily stretched the wing is. Also, in general, the amount the wing can be stretched before breaking is maximum parallel to the corrugations. It is noted that the dactylopatagium had the greatest chenage in modulus depending on pull direction compared to all of the wing regions, showing an 86% decrease in stiffness going from testing perpendicular to the major corrugations to parallel with them. The membrane of the uropatagium showed little directionality and it is noted that in concert with this there was very little visual evidence of corrugations in the skin material. From this point is it surmised that the corrugations themselves have an important role in the properties of the bat wing membrane. Using all of this knowledge, the data could be applied to micro-air vehicles (MAVs). Vehicles that use flapping flight (ornithopters) have been an unachievable goal until recently. Part of the problem was that a suitable wing skin could not be found that behaved like natural wings yes retained its strength under use. The properties of natural bat wings were investigated, and an interesting microstructure was found to correlate heavily with the direction of strength of material was well as the yield point of the wing skin. This principle can be used in the development of artificial wings.

National Science Foundation (NSF)
Office of International and Integrative Activities (IIA)
Application #
Program Officer
Carter Kimsey
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Smith Colin F
United States
Zip Code