image: Bistable mechanical linkage. A transition wave propagates through the entire linkage and transforms the initial straight configuration into a curved one. view more
Credit: Image courtesy of Ahmad Zareei.
Transition waves provide a platform for realizing deployable structures that can be expanded quickly and locked into place after deployment, according to a study. Deployable structures, such as the everyday umbrella, are characterized by two stable states and are used in myriad applications from aerospace to medical systems. Ahmad Zareei and colleagues explored the use of transition waves to improve the reliability and autonomy of deployment. The authors developed a mechanical linkage containing an array of rigid bars connected by bistable joints, a type of joint characterized by two stable positions. The authors demonstrated that, if the linkages are properly designed, a state transition wave propagates through the links and sequentially switches all of the joints in a domino-like effect. Propagation of this state-transitioning wave, monitored with a high-speed camera, transformed a straight line of bistable joints into a stable, locked curve. The authors used the linkages as building blocks to create an array of deployable 3D structures of arbitrary shapes. According to the authors, though the experiments were done at the centimeter scale, the approach can be extended to larger structures provided the energy stored in the joints is sufficient to account for gravity and dissipation.
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Article #19-17887: " Harnessing transition waves to realize deployable structures," by Ahmad Zareei, Bolei Deng, and Katia Bertoldi.
MEDIA CONTACT: Katia Bertoldi, Harvard University, Cambridge, MA; tel: 617-496-3084; e-mail: <bertoldi@seas.harvard.edu>
Journal
Proceedings of the National Academy of Sciences