Programmable filaments and textiles

Abstract

We analyze the various morphing structures obtained by actuating Janus filaments comprising driven and passive sectors and textiles incorporating driven and passive filaments. Transitions between alternative shapes and coexistence of absolutely stable and metastable states within a certain range of relative extension upon actuation are detected both in Janus rings and textiles. Both single filaments and textiles can be reverse designed to bend into desired shapes by controlling both the size and orientation of driven sectors. arXiv:1903.05943v1 [cond-mat.soft]

Mechanochemical induction of wrinkling morphogenesis on elastic shells

“…Tissue morphogenesis can inspire the design of such slender structures that change shape in a programmable way. Desired shapes can be attained by pre-patterning the internal structure, for example via metric change [10][11][12], controlled intrinsic curvature [13,14], prestress [15], or be self-organized, for example, through a propagating chemical reaction coupled with mechanical deformations [16][17][18][19]. The latter approach provides reconfigurable conformations in contrast with frozen-in patterns, and resembles the shape changes during morphogenesis with anisotropic deformations including different types of mechanical instabilities, such as creases, wrinkles, folds, and ridges [20].…”

Fiber-based shape-morphing architectures

“…Straightforward computation experiments allow us to predict twisting angles and lowest-energy configurations of frame structures. Our theory can be extended to more complex structures [16] and more sophisticated ways of actuation. The shape transformation was studied here for centimeter-scale macroscopic structures but the results are scalable and remain valid for fibers with proportionally reduced geometric parameters.…”

“…2b), and the orientation of the dividing plane varies along its length. Earlier theoretical studies showed [16,17] that the shape of a Janus ring is governed by the ratio R 0 /R dependent on the extension coefficient, and can exist in multiple states, following discontinuous transitions between shapes with a different number of "petals". The linear stability analysis of an untwisted ring predicts the following numerical values R 0 /R = 3.2, 6.6 and 11.3 for the transitions to shapes with 2, 3, 4 petals, respectively.…”

“…To gain further insight into the origin of out-of-plane actuation detected in the experiments, we investigated the interplay between bending and twisting energies, which are difficult to distinguish experimentally. For this aim, we applied the analytical theory [16] to the results presented in Fig. 3d for a frame with a symmetric actuation of Janus filaments developing curvature in the frame plane, and demonstrate the transition to a twisted shape.…”

“…As a result, a few percent of linear elongation or contraction can be converted into a considerable angular deflection. However, shape transformation of bilayers is limited to simple bending, whereas combining shape-changing and passive fibers allows one to circumvent this issue and generate complex, predictable shape transformations [16,17]. In this paper, we investigate experimentally and theoretically the variety of shape transitions in structures actuated by composite Janus fibers (named by the two-faced Roman god).…”