Shape formation of helical ribbons induced by material anisotropy

Helices are ubiquitous building blocks in natural and engineered systems. Previous studies showed that helical ribbon morphology can result from anisotropic driving forces and geometric misorientation between the principal axes of the driving forces and the geometric axes. However, helical ribbon shapes induced by elastic modulus anisotropy have not been systematically examined even though most natural and engineered structures are made of composite materials with anisotropic mechanical properties. We build on a previously developed model using continuum elasticity and stationarity principles to predict helical ribbon shapes induced by material anisotropy under both isotropic and anisotropic pre-stretching conditions. Results from finite element analysis and table-top experiments showed that the principal curvatures, chirality, and helix angles can be further tuned in anisotropic ribbons under both isotropic and anisotropic pre-stretching conditions. This work can promote programmable design and fabrication of curved structures and devices.

Appl. Phys. Lett. 110, 091901 (2017); doi: http://dx.doi.org/10.1063/1.4977090

http://aip.scitation.org/doi/abs/10.1063/1.4977090