Inspired by the simplicity and the mechanism behind vintage push puppet toys, a trailblazing team of engineers from the University of California, Los Angeles (UCLA) has designed a unique and dynamic metamaterial that is tunable and shape-changing.
Common push puppet toys are designed in the shapes of animals and figures, standing stiff, or collapsing as a button at the base of the toy is pushed. These toys consist of connecting cords that stand stiff when pulled tight. Put simply, the tightness or looseness of these cords, or "limbs," in the puppet, dictates the puppet's physical state. Building on this cord tension principle, the engineering team at UCLA has succeeded in developing an innovative kind of metamaterial that has properties with superior capabilities and potential cross-sector uses.
The innovative metamaterial is characterized by its light weight and is embedded with either self-actuating or motor-driven cords that have been threaded through interlocking cone-tipped beads. When the corresponding cords are activated and pulled tight, the enmeshed chain of bead particles proceeds to jam and straighten into a linear arrangement. This action stiffens the metamaterial while still arresting its overall structure.
Further adding to the versatility of this metamaterial is the degree of tension in the cords. The stiffness of the resulting structure can be "tuned" through the level of tension in the cords. A completely taut state brings about a stiff and robust level, but even minute changes in the cords' tension permit the structure to flex whilst offering strength.
Additional attributes include the capacity for structures utilizing this design to repeatedly collapse and stiffen, a factor which is critical for long-haul designs that necessitate frequent movement. The metamaterial allows for uncomplicated transportation and storage when in an undeployed state. Post deployment, the material shows noticeable tunability, becoming more than 35 times stiffer and altering its damping capacity by 50%.
According to Wenzhong Yan, the corresponding author and a postdoctoral scholar at UCLA Samueli School of Engineering, this metamaterial offers extensive potential for addition into a range of applications, including robotics, reconfigurable structures, and also space engineering. Robots built from this material could calibrate their limbs' stiffness to match different terrains optimally while maintaining their body structure.
Presently, there is a massive scope for tailoring and customizing capabilities by changing the beads' shapes and sizes, as well as their connections. While some previous research has studied contracting cords, this paper ventures into the mechanical properties of such systems, delving into ideal bead alignment, the potential for tuning, self-assembly, and the overall framework preservation.
Published in the journal Materials Horizons, the pioneering research was funded by various bodies, including the Office of Naval Research, the Defense Advanced Research Projects Agency, and the Air Force Office of Scientific Research. Additional support came from the UCLA Office of Advanced Research Computing.
Disclaimer: The above article was written with the assistance of AI. The original sources can be found on ScienceDaily.
