Nature Communications Publishes New Research by Tubaldi
Eleonora Tubaldi, assistant professor of mechanical engineering, has published new work in Nature Communications that details a promising new approach to exploiting the properties of architected cellular materials, which are artificially engineered materials composed of repeated porous microstructures or lattice structures similar to those found in tree bark or cork.
Such materials often exhibit unusual properties, such as augmented strength, energy, absorption capacity, and flexibility. They can also be “smart”—that is, able to detect and respond to external conditions. Applications abound in fields such as soft robotics and advanced manufacturing.
Tubaldi’s paper, “Soft porous metamaterials using inflation-induced buckling for smart actuation” presents a new class of so-called “SPoNGe” metamaterials that are soft, porous, nonlinear, and geometric—hence the acronym. Through computer modeling, numerical analysis and subsequent experimentation, she and her research team at the University of Maryland (UMD) found these novel materials can potentially unlock superior programming capabilities for soft intelligent machines.
The materials, whose structure consists of repeated, cylinder-shaped cells surrounded by a pressure cavity, buckle in a range of predictable ways with the application of pressure from a single input, and can be “tuned” to produce a number of reconfiguration patterns, such as ellipses and diamonds. Tubaldi’s team was able to demonstrate their applicability by using them to engineer a smart gripper as well as a device that can be used to operate fluidic channels, which often form the “circuitry” of soft robots.
“We are excited to introduce the first metamaterial showcasing buckling upon inflation,” Tubaldi said. “Historically, buckling instabilities in soft porous mechanical metamaterials have enabled repeatable, large, and fast pattern reconfigurations which are appealing for multifunctional robotic applications. While it is well known that metamaterials with arrays of pores or voids can undergo buckling under compressive forces or negative pressure (i.e., vacuum), this instability upon inflation has never been mathematically predicted nor experimentally observed.”
“With our new porous metamaterial, we demonstrate analytically, numerically, and experimentally how to achieve different global buckling mode shapes by controlling the number of lobes of the collapsing pores and the alignment of neighboring elements,” she said.
She and her team combined these results to design a soft gripper with distributed touch-points and sequencing capabilities, which is able to selectively grasp slender and delicate objects with a single pressure inlet. In addition, Tubaldi said, the paper showcases how their metamaterial can control and dispense two fluids in specified ratios.
The team, Tubaldi noted, conducted “a fun demo involving targeted coffee and cream ratios, because each coffee lover has a favorite ratio!”
“Our work provides the foundation for future efforts in unlocking superior programming and sequencing capabilities while expanding the design space of soft intelligent machines," she said.
This is the third publication in Nature Communications within the past four years for Tubaldi. In 2024, the journal published aerogel research she conducted in collaboration with UMD Chemical and Biomolecular Engineering Assistant Professor Po-Yen Chen. In 2021, it featured a paper by Tubaldi and collaborators on using arch-like structures to generate and harness non-reciprocity, that is, a state in which energy is transmitted asymmetrically between two points.
A graduate of McGill University (Ph.D.), Ecole Polytechnique de Montreal (M.S.), and Politecnico di Milano (M.S./B.S.). Tubaldi has been a member of the UMD mechanical engineering faculty since 2020. In 2023, the National Science Foundation (NSF) awarded her its most prestigious award for early-career researchers, the NSF CAREER Award, to support her work on metamaterials.
The new paper’s authors include three researchers from the Tubaldi Lab at UMD: Kieran Barvenik,. Michael Bonfron, and Anthony Jones.
The materials, whose structure consists of repeated, cylinder-shaped cells surrounded by a pressure cavity, buckle in a range of predictable ways with the application of pressure from a single input, and can be “tuned” to produce a number of reconfiguration patterns, such as ellipses and diamonds. Tubaldi’s team was able to demonstrate their applicability by using them to engineer a smart gripper as well as a device that can be used to operate fluidic channels, which often form the “circuitry” of soft robots.