South Dakota Mines Engineers Win Second Place in National Bridge Contest with Lightweight Composite Design

South Dakota School of Mines and Technology (Rapid City, SD, US) announced Aug. 14 that students took home second place in the Society for the Advancement of Material and Process Engineering (SAMPE, Diamond Bar, CA, US) 2018 Student Bridge Contest, by designing a bridge weighing just 12.5 ounces that can carry a 2,000-lb load.   
 
Mines students engineered the design of the bridge using a proprietary composite sheet material invented by a team of researchers at Mines’ Composite and Nanocomposite Advanced Manufacturing Center (CNAM)  and Composites and Polymer Engineering (CAPE) Laboratory.  By bonding the unique CNAM material, called Discontinuous Fiber Thermoplastic Sheet (DiFTS), to the top and bottom of a lightweight honeycomb core in a suitable thicknesses ratio, the students were able to engineer the properties of the laminated sandwich structure to meet the load requirements of the competition, while maintaining low overall density. The DiFTS material incorporates short, recycled carbon fiber embedded in a thermoplastic matrix, whereby uniform fiber distribution, significant fiber alignment, effective fiber length retention, and thorough fiber encapsulation result in high-performance properties using a low-cost process.
 
“It is not that CNAM has developed a super-material; it is that we developed a low-cost, high performance, environmentally sustainable composite that can be demonstrably engineered to meet demanding load-bearing requirements, and which competes very favorably against traditional high-cost carbon fiber composites,” says team advisor, Professor David Salem, Ph.D., director of the CNAM Center and the CAPE Laboratory.
 
The SD Mines bridge team included Matthew Phillips, senior in math and mechanical engineering; Schmid, a Ph.D. student in the Nano Science and Engineering Program; and Krishnan Veluswamy, a Ph.D. student in the Materials Engineering and Science Program, who also won the 2018 SAMPE International University Leadership Experience Award. “It’s exciting that this bridge was made from in-house materials developed at Mines,” says Veluswamy. “This kind of material has industrial applications across the board, from sporting goods to automobiles to airplanes, because it’s strong, lightweight and inexpensive to manufacture.”
 
A sister center – the CNAM Biomaterials Center (CNAM-Bio) – has recently been launched at SD Mines and is undertaking research on plant based biodegradable plastics, natural biofibers and biocomposites that could someday merge with this technology, further enhancing the DiFTS environmental sustainability.