Ann Arbor Times

Researchers from the University of Michigan and the Air Force Research Laboratory have demonstrated a new way to reduce vibrations using 3D-printed structures known as mechanical metamaterials. The team’s study, published in Physical Review Applied, details how these intricately designed tubes, called kagome tubes, can stifle vibrations through their geometric structure.

Mechanical metamaterials are engineered materials whose properties arise not from their chemical composition but from their shape and design. “For centuries, humans have improved materials by altering their chemistry. Our work builds on the field of metamaterials, where it is geometry—rather than chemistry—that gives rise to unusual and useful properties,” said Xiaoming Mao, professor of physics at the University of Michigan and co-author of the study. “These geometric principles can apply from the nanoscale to the macroscale, giving us extraordinary robustness.”

The research team used advanced 3D printing techniques to fabricate nylon-based structures that passively impede vibrations moving through them. James McInerney, a research associate at AFRL who previously worked at U-M with Mao, explained: “That’s where the real novelty is. We have the realization: We can actually make these things.” He added, “We’re optimistic these can be applied for good purposes. In this case, it’s vibration isolation.”

This project was funded in part by federal agencies such as DARPA and the Office of Naval Research and also received support through a U.S. National Research Council program administered by the National Academies of Sciences, Engineering and Medicine.

Serife Tol from U-M’s Department of Mechanical Engineering contributed to the study alongside collaborators from other institutions including Othman Oudghiri-Idrissi (University of Texas) and Carson Willey and Abigail Juhl (AFRL).

The idea behind this research draws on historical scientific concepts such as Maxwell lattices—repeating structural units developed in part by 19th-century physicist James Clerk Maxwell—and recent advances in topology that investigate unique behaviors near material boundaries.

“About a decade ago, there was a seminal publication that found out that Maxwell lattices can exhibit a topological phase,” McInerney said.

By applying models built over several years to actual objects fabricated via 3D printing, researchers observed that while these kagome tube structures suppress vibrations effectively, they do so at the expense of load-bearing capacity—a tradeoff that could affect practical applications.

McInerney noted that more work remains before these materials can be widely adopted: “Because we have such new behaviors, we’re still uncovering not just the models, but the way that we would test them, the conclusions we would draw from the tests and how we would implement those conclusions into a design process,” he said. “I think those are the questions that honestly need to be answered before we start answering questions about applications.”