Many xeric plant leaves exhibit bending and twisting morphology, which may contribute to their important biological and physical functions adapted to drought and desert conditions. Revealing the relationships between various morphologies and functionalities can inspire device designs for meeting increasingly stringent environmental requirements.
Liquid crystal elastomers (LCEs), as a unique class of smart soft materials combining the properties of liquid crystals and hyperelasticity, are capable of rapid, anisotropic, and reversible deformations in response to mechanical, thermal or optical stimuli. Here, we report a hitherto unknown stretching-induced twisting behavior of LCE bilayer strips. Under uniaxial stretching, we reveal that due to the spontaneous mismatch strain arising from interlayer anisotropy, the bilayer strips exhibit notable twisting deformations.
Thin films usually exhibit instabilities and yield intricate wrinkles when two clamped ends are twisted. Here, we explore the wrinkling behavior and pitch-fork bifurcation of twisted thin films experimentally and theoretically. To quantitatively predict the post-buckling evolution of twist-induced wrinkling morphology, we develop a refined finite-strain plate model derived from 3D field equations and then solve it by using the finite element method with COMSOL. We examine the effects of aspect ratios and pre-tension on the wrinkling profile.
How can we induce twist in tubular structures without applying a torque?
In nature, such behavior is enabled by material anisotropy. In our new work, we show that isotropic bi-layer tubes with twist incompatible layers can twist upon inflation and extension.
Interestingly, the direction of twist can spontaneously reverse as the load increases!
Check out our new paper at EML:
https://www.sciencedirect.com/science/article/pii/S2352431621000766
Self-shaping of curved structures, especially those involving flexible thin layers, is attracting increasing attention because of their broad potential applications in, e.g., nanoelectromechanical andmicroelectromechanical systems, sensors, artificial skins, stretchable electronics, robotics, and drug delivery.
