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World's First Carbon Nanofiber Bridge Debuts

02 June 2003

University of Dayton (UD) SAMPE Student Chapter members recently constructed what they believe is the world's first bridge to contain carbon nanofibers, dubbed the ‘World's First Carbon Nanofiber Bridge’.

The activity was part of the SAMPE 6th Annual Super Light-Weight Composite Bridge Building Contest on May 13 in Long Beach, California.

UD Engineering students developed a bridge design that combined innovative sandwich structural design with braided fabric composite materials and carbon nanofibers. The carbon nanofiber bridge won two prizes in the Contest: 2nd place in testing in the category of "braided bridge, kit materials", and 2nd place in the student poster contest. The bridge supported a load of 2,136 lbs. and weighed only 0.965 lbs., for an "efficiency ratio" of 2214:1.

This result was 55% greater than bridges of the same design not containing carbon nanofibers that were previously tested at UD using the same test fixture and parameters. The improvement was attributed to the increase in the resin modulus resulting from the nanofibers, which in previous testing was observed to increase by a factor of 2.5 times at a nanofiber loading of 4 wt% (of the resin). The resin modulus is widely known to have a significant impact in resin-dominated composite properties such as compressive strength and interlaminar shear strength.

The goals of the UD nanofiber bridge project were several fold: to demonstrate the tangible, multifunctional benefits of currently available and affordable carbon nanofibers, to publicize that the Dayton area is a leader in nanomaterial technology development and commercialization, to stimulate collaboration among several Dayton area organizations and UD in the area of nanomaterials, and to provide an invaluable cross-disciplinary engineering project for UD undergraduate and graduate students. These goals were accomplished through designing and building a bridge that combined mechanical strength and robustness, light weight, and improved heat transfer and electrical conductivity. The primary technical objective was to demonstrate mechanical property improvements with the addition of a small amount (4 wt%) of carbon nanofibers.

Several local companies sponsored the project, including National Composite Center, Applied Science Inc., and A&P Technologies Inc., as well as the University of Dayton Research Institute. A contingent of six UD Engineering students attended the SAMPE Conference to participate in the bridge building contest.

The SAMPE Super Light-Weight Composite Bridge Building Contest is in its sixth year. Organized by Dr. Howard Kliger (H.S. Kliger and Associates, Edison, NJ), this contest is held at the International SAMPE Symposium and Exhibition (ISSE), and it has grown in popularity and participation since its inception. The goal is to build a lightweight "bridge" that maximizes the ratio of bending strength to bridge weight. The bridges are 24 inches long and have a 4-inch-wide "road surface". There are different categories based on the types of materials used, with carbon fiber composite materials being used the most often historically. Prizes are awarded to the bridges scoring the highest strength-to-weight ratio. Usually there are additional prizes awarded for other criteria.