Composite Bridge Winners Use Lightweight, Strong, Inexpensive Material Developed at SD Mines

Krishnan Veluswamy, a Ph.D. student in the Materials Engineering and Science Program at SD Mines, holding the bridge his team built and his 2018 SAMPE International University Leadership Experience Award.

South Dakota School of Mines and Technology students took home second place in the Society for the Advancement of Material and Process Engineering (SAMPE) 2018 Student Bridge Contest, by designing a bridge weighing just 12.5 ounces that can carry a 2,000-pound load.

The competition, held in Long Beach, Calif., pitted SD Mines researchers against 70 teams from 30 universities from around the world. Teams were tasked to design, build and test a 24-inch-long structural composite bridge using fiber reinforced plastics and high-performance materials. The annual event challenges teams to make bridges that carry a specified load while also being as lightweight as possible. The Mines bridge placed second in the inaugural year of the sandwich beam category at SAMPE’s bridge contest.

“The SAMPE bridge competition is a fantastic opportunity for students to develop some hands-on composite fabrication skills and to see how the process side of composites engineering truly impacts their final performance,” says Eric Schmid, SD Mines bridge team member and SAMPE North America Young Professionals committee chair. “SAMPE provides an excellent platform for students to demonstrate their capabilities, and the chance to attend the SAMPE conference and bridge competition really gives students a great view of how important composites are across many different industries.”

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.

“The CNAM-DiFTS material itself was developed over several years by CAPE/CNAM research scientists and engineers, and as we enter the commercialization phase, it was certainly gratifying to see its cost/performance advantages displayed so clearly at a major conference and exhibition,” says Salem.

Both Schmid and Veluswamy also recently attended the "It's All About Science Festival” at Sanford Research Center in Sioux Falls, where they showcased their SAMPE bridge, a 3D printer in action and other examples of composite materials for K12 students and their families. Approximately 3,000 community members attended the event, which included more than 50 booth exhibits and numerous STEM demonstrations. Veluswamy also won an honorable mention in the graduate poster competition for his work titled, “Thermoplastic Fiber Reinforced Composites,” which explained how the composite materials used in the SAMPE bridge were made.


Last edited 10/2/2023 10:29:01 PM

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