ERDC’s Advanced Materials Initiative Produces 2nd Generation Super Fiber Design

Published Sept. 5, 2012
Dr.Cornwell and Dr. Welch

Dr.Cornwell and Dr. Welch

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VICKSBURG, Miss. -- ERDC Information Technology Laboratory (ITL) Researchers Drs. Charles Cornwell and Charles “Bob” Welch’s work on carbon nanotube bundles was recently featured in the July 25th issue of the Molecular Simulations journal.

The article, “Brittle Ductile Transition in Carbon Nanotube Bundles,” is based on Cornwell’s research into using multi-million atom molecular dynamics simulations to analyze designs of fibers composed of carbon nanotubes (CNT) to optimize fiber tensile strength or fiber toughness.  The molecular dynamics simulations considered the forces between each atom and between each molecule and are arguably some of the most advanced simulations of CNT fibers.  The simulations take advantage of ERDC’s access to high-performance computers through the Department of Defense’s High Performance Computing Center at ERDC.

The fibers analyzed by Cornwell employed interstitial carbon atom cross-links between the CNTs to enhance load-sharing.  By varying the density of the cross-links, fibers of high strength and low ductility, or high ductility but lower strength, could be produced.  The predicted fiber strength varied between 55 GPa (8 million psi) to 20 GPa (2.9 million psi), or between 80 to 29 times the tensile strength of high-strength steel.

This research is part of ERDC’s Advanced Materials Initiative (AMI) which is co-led by Welch, and is being conducted by the Geotechnical and Structures Laboratory, ITL, Construction Engineering Research Laboratory, and the Environmental Laboratory.  The AMI team, led by Dr. Charles Marsh, is attempting to synthesize a million-psi version of the fiber by plasma-irradiation of aligned CNTs.  Similar fiber synthesis efforts using electron-beam irradiation are under way at NASA, Northwestern University and Cambridge University.

“AMI is a great example of ERDC using nanotechnology to enhance civil and military engineering,” said Welch.