New technology improves structural strength

In a collaborative effort between Texas A&M University and Sandia National Laboratories, researchers have significantly improved a new joining technology, interlocking metasurfaces (ILMs), designed to increase strength and stability of a structure in comparison to traditional techniques such as bolts and adhesives, using shape memory alloys (SMAs). ILMs could transform mechanical joint design in manufacturing for aerospace, robotics, and biomedical devices.

“ILMs are poised to redefine joining technologies across a range of applications, much like Velcro did decades ago,” says Dr. Ibrahim Karaman, professor and head of the Department of Materials Science and Engineering at Texas A&M. “In collaboration with Sandia National Laboratories, the original developers of ILMs, we have engineered and fabricated ILMs from shape memory alloys. Our research demonstrates these ILMs can be selectively disengaged and re-engaged on demand while maintaining consistent joint strength and structural integrity.”

These findings are published in Materials & Design.

ILMs join two bodies by transmitting force and constraining movement. Until now, this joining method has been passive, requiring force for engagement.

Using 3D printing (3DP), the teams designed and fabricated active ILMs by integrating nickel-titanium shape memory alloys (SMAs), which can recover their original shape after deformation by changing temperatures.

Control of joining technology through temperature changes opens new possibilities for smart, adaptive structures without loss in strength or stability and with increased options for flexibility and functionality.

“Active ILMs have the potential to revolutionize mechanical joint design in industries requiring precise, repeatable assembly and disassembly,” says Abdelrahman Elsayed, graduate research assistant in the materials science and engineering department at Texas A&M.

Practical applications of ILMs include designing reconfigurable aerospace engineering components where parts must be assembled and disassembled multiple times. Active ILMs could also provide flexible and adaptable joints for robotics.

Current findings used the shape memory effect of SMAs to recover the ILMs’ shape by adding heat. The researchers hope to build on these findings by using the superelasticity effect of SMAs to create ILMs that can withstand large deformation and instantaneously recover under very high stress levels.

“Achieving superelasticity in complex 3D-printed ILMs will enable localized control of structural stiffness and facilitate reattachment with high locking forces,” Karaman says.

Other contributors include Dr. Alaa Elwany, associate professor in the Wm Michael Barnes ’64 Department of Industrial and Systems Engineering, and doctoral student Taresh Guleria in the industrial systems and engineering department.

Funding for this research is administered by the Texas A&M Engineering Experiment Station (TEES), the official research agency for Texas A&M Engineering.

Sandia National Laboratories
https://www.sandia.gov

Texas A&M University
https://www.tamu.edu