WEST LAFAYETTE, Ind. — Purdue University researchers are working with the U.S. Army Research Laboratory to develop a technology for creating parts out of interlocking segments produced using 3D printing to repair vehicles and other equipment in the field.

The Purdue portion of the research focuses on building blocks called "topologically interlocking structures" said Thomas Siegmund, a professor of mechanical engineering.

"You could think of it as clever Legos," said Siegmund, currently on leave from Purdue to serve as program director of the Mechanics of Materials Division at the National Science Foundation. "We create a shape from individual pieces or building blocks.”

The building blocks could be in the shape of cubes, faceted tetrahedral or other geometries, and might be created layer-by-layer using a 3D printer. Then, these components might be assembled into parts for vehicles or other equipment.

Purdue postdoctoral research associate Yuezhong Feng creates an interlocking structure using a 3-D printer. Purdue researchers are working with the U.S. Army Research Laboratory to develop a technology for creating parts out of interlocking segments produced using 3-D printing to repair vehicles and other equipment in the field.Purdue University/Steven Yang "The surface topology is important because these building blocks have to be arranged relative to each other in an appropriate fashion that functions," said Siegmund, working with postdoctoral research associate Yuezhong Feng. "You could make a brick wall in the classical sense, one brick on top of another. But then they can easily be knocked out of place. However, if you take the same bricks and tilt them so the edges are facing you, you get this topological interlocking structure, one inclined face interlocking with the next inclined face, and so on."

Such interlocking structures might be able to absorb vibration and withstand shock better than conventional structures. The researchers are developing computational models and conducting experiments in a laboratory in the Mechanical Engineering Building.

Parts might be created from layers or particles, an approach called "additive manufacturing," Siegmund said.

"In our case we create each geometrical building block and then go to the next dimension by layering these building blocks into parts," Siegmund said. "So it's a multidimensional additive manufacturing."

Purdue is collaborating with the Army Research Laboratory, and the Army Research Office funds the work.

Siegmund also is leading related work funded by the Air Force Office of Scientific Research and the Defense University Research Instrumentation Program that has been supported by the Indiana 21st Century Research and Technology fund and Purdue's Center for Advanced Manufacturing.

The research focuses on developing "metamaterials" possessing new mechanical and acoustical properties.

"These materials obtain their properties not from composition but structure, and have the potential to possess properties not found in natural materials," he said. "The materials possess ideal damage tolerance and can be hybridized by changing both composition and structure."

More information about the Army Research Laboratory project is available at http://www.army.mil/article/109144/Army_Research_Lab__Purdue_explore_3_D_printing_to_fix_deployed_equipment__cut_maintenance_costs/