Award Abstract #0848894
Complex surface structure and locomotion

NSF Org:	PHY Division of Physics
Initial Amendment Date:	September 3, 2009
Latest Amendment Date:	July 1, 2011
Award Number:	0848894
Award Instrument:	Continuing grant
Program Manager:	Krastan B. Blagoev PHY Division of Physics MPS Directorate for Mathematical & Physical Sciences
Start Date:	September 1, 2009
Expires:	August 31, 2013 (Estimated)
Awarded Amount to Date:	$389,933.00
Investigator(s):	David Hu hu@me.gatech.edu (Principal Investigator)
Sponsor:	Georgia Tech Research Corporation Office of Sponsored Programs Atlanta, GA 30332-0420 (404)894-4819
NSF Program(s):	PHYSICS OF LIVING SYSTEMS
Program Reference Code(s):	0000, 9183, OTHR
Program Element Code(s):	7246

ABSTRACT

In this project the PI will investigate, experimentally and theoretically, the role of complex biological integuments in animal locomotion. Two parallel research thrusts are planned: one investigation on the terrestrial limbless locomotion of snakes, and the other on the collective locomotion of semi-aquatic insects. A series of integrated experimental and theoretical investigations will be conducted on the propulsion of snakes on horizontal surfaces. Snakes exhibit four modes of locomotion, including lateral undulation, side winding, rectilinear progression and an accordion-like concertina motion. The goal of this research is to rationalize these limbless propulsion mechanisms. An existing theoretical framework will be adapted for investigation of the snake gaits. Particular attention will be given to assessing the snake's gains in efficiency and speed from dynamic lifting of its body during locomotion. Measurements of the snake's weight distribution during slithering will be obtained qualitatively using birefringent gelatin techniques and quantitatively using arrays of pressure transducers. An understanding of dynamic load-bearing mechanisms will shed insight onto the snake's energy budget and mechanisms for reducing abrasive wear. For the second part of the project, combined experimental and theoretical investigations will be made on the locomotion of insects that live above and below the water surface. An exploratory investigation will be conducted on the mechanisms by which fire ant colonies, whose individuals are hydrophilic and cannot swim, collectively form floating structures, ant balls that allow them to survive floods. Contact angles of the individuals and frozen ant balls will be measured and the dynamics of ants within the ball observed. A series of investigations of the locomotion of aquatic insects and gastropods will also be conducted, focusing on their wetting properties, propulsion using cilia and the body shapes which give them underwater stability near the free surface. The PI will develop an interdisciplinary undergraduate course in animal bio-locomotion in order to draw together students of biology and engineering and increase the visibility of integrative research. A bio-inspired walking-on-water theme will be planned for the school's annual design competition for mechanical engineering juniors. The PI will mentor two local high school students under the Intel Science Talent Search, in which he once participated.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

H. Marvi, D. Hu. "Friction Enhancement in Concertina Locomotion of Snakes," Journal of the Royal Society Interface, 2012.

Dickerson, A.K. and Mills, Z.G. and Hu, D.L. "Wet mammals shake at tuned frequencies to dry," Journal of the Royal Society Interface, v.10.1098, 2012.

H. Marvi, J. Bridges, D. Hu. "Snakes Mimic Earthworms: Propulsion Using Rectilinear Traveling Waves," Journal of the Royal Society Interface, 2013.

Dickerson, A.K. and Shankles, P.G. and Madhavan, N.M. and Hu, D.L. "Mosquitoes survive raindrop collisions by virtue of their low mass.," Proceedings of the National Academy of Sciences, v.109, 2012.

Bush JWM and Hu DL. "Walking on water," Physics Today, 2010.

Hu D and Goldman D. "Wiggling through the World," American Scientist, 2010.

H. Marvi, D. Hu,. "Friction Enhancement in Concertina Locomotion of Snakes," Journal of the Royal Society: Interface, 2012.

Dickerson, A., Mills, Z. & Hu, D.L.. "Wet mammals shake at tuned frequencies to dry," Journal of the Royal Society: Interface, 2012.

Hu, D.L., Nirody, J., Scott, T., Shelley, M.J. "The mechanics of slithering locomotion," Proceedings of the National Academy of Sciences, USA, 2009.

Dickerson, A., Shankles, P., Madhavan, N., & Hu, D.L.. "Mosquitoes survive raindrop impacts by virtue of their low mass," Proceedings of the National Academy of Sciences, USA, 2012.

BOOKS/ONE TIME PROCEEDING

Hu DL and Shelley MJ. "Slithering locomotion", 09/01/2010-08/31/2011, , Childress S"Natural locomotion in fluids and on surfaces",  2011, "Elsevier, to be published by the IMA (Institute for Mathematics and its Applications)".

Marvi H, Meyers G, Russel G and HU D. "Scalybot: a snake-inspired robot with active control of friction", 09/01/2010-08/31/2011, "ASME Dynamic systems and control conference proceedings",  2011, "ASME".

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