Twisters: an analogy of bilayers for twisting
Abstract
Benders, such as bilayers, are well-known shape-changing structures which bend upon activation by a stimulus, such as temperature. The objective of this contribution is to propose new shape-changing rod-like structures, referred to as twisters, which twist upon activation. A simple biomimetic design principle based on symmetry considerations is proposed and used to derive a mechanical model. The kinematics of the response of the twister to the simulus is inspired from FEM simulations, and slightly simplified to allow for an analytical resolution of the governing equations. Proposed twisters are shown to first stretch as the stimulus increases until a bifurcation is reached, then, they undergo a mixed stretching-twisting regime. An accurate approximation of the bifurcation point is derived and serves as a guideline for the design of twisters in accordance with chosen specifications. Results are illustrated using twisters with three different behaviours. The methodology can be straightfowardly extended to more complex kinematics and other constitutive laws.
Origin : Files produced by the author(s)
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