video: A simulation of two surfaces designed to interlock.
Credit: Albert To and Myung Kyun Sung
Connecting unlike materials such as titanium with nickel can pose a unique engineering challenge, especially if the connections must perform under extreme conditions. As systems grow increasingly complex, bolts, adhesives, and welding can only go so far.
Albert To, William Kepler Whiteford Professor, along with Wei Xiong, associate professor & William Kepler Faculty Fellow, in the Department of Materials Science and Mechanical Engineering at the University of Pittsburgh Swanson School of Engineering, have received a $400,000 Defense Advanced Research Projects Agency (DARPA) award to develop novel interlocking design and fabrication technology for complex defense, aerospace, transportation, energy, and medical systems.
Their project, “Enabling Design and Fabrication of Multi-Functional, Multi-Material Structures with Interlocking Interfaces,” seeks to transform how dissimilar surfaces connect, leading to stronger, more resilient systems that can withstand heat, stress, and other demanding conditions.
“Traditionally, we have welded, bolted, or used adhesives to connect surfaces,” said To. “However, with new technology like hypersonic vehicles, those approaches can be insufficient. We need to rethink how we form stronger bonds.”
Instead of relying on the adhesion where materials meet, To’s group has developed a novel process that harnesses the inherent strength of each material. They are using advanced computational design that focuses on the topology, or the way geometric objects function as they are transformed, to develop structures that lock together, no matter how incompatible their surfaces.
“We want to make a handshake between two materials,” To said. “The materials will lock into each other geometrically, so when you try to pull them apart, the joint remains firm.”
These structures are fabricated using additive manufacturing, or 3D printing, ensuring rapid and custom production.
“Our computer simulations show that optimized interlocking interfaces can double the strength at the point of connection relative to human-designed baselines,” said Myung Kyun Sung, a postdoctoral associate in mechanical engineering at the Swanson School, who has helped To research this new technology. “We found a significant increase in effective stiffness and tensile strength.”
Ultimately, the research could expand the types of materials that can be connected, opening a range of design possibilities across industries.
“This project seeks to transform how we join materials,” To said. “By making it easier and less expensive to join different surfaces, we can develop everything from stronger aerospace structures to more advanced medical devices.”