Shape Programming by Modulating Actuation over Hierarchical Length Scales

Abstract

Gaussian morphing", that is, the spatial programming of in-plane deformations, or metric distortion, inducing a change in Gaussian curvature. [6-9] In many systems, the deformation is anisotropic and has a uniform magnitude, but can be oriented along a director field. This is the case of liquid crystal elastomers (LCE), [10-15] pneumatic elastomers, [16] the biological sliding of Euglena, [17] photoresponsive materials, [18,19] swelling restricted by oriented fibers, [20-22] or 3D printed thermo-responsive filaments. [23,24] Several approaches were used to determine the director field that will generate a target 3D shape, [13,25] but this inverse problem is difficult and there is no guarantee that a solution exists in general. Using a larger family of metrics could ease this inverse problem. In

Wood Warping Composite by 3D Printing

“…Here, for simplicity, we printed only along straight lines. but introducing curved lines [26], zigzags [27], and fractal Hilbert patterns [28] will greatly extend the possible outcomes. Furthermore, the presented approach can be implemented in other systems, such as hydrogels, and by carefully altering the characteristics of the ink, the effect of printing velocity on the induced orientation can be enhanced.…”

Shape Control, Morphing and Mechanobiology

“…Gaussian morphing [24], which uses modulation of in-plane stretches in order to produce Gaussian curvature as predicted by Gauss's Theorema Egregium, is an alternative avenue to shape programming of thin sheets. This approach has been pioneered by E. Sharon and collaborators [53] and has seen applications to a wide variety of material systems such as biological tissues experiencing growth, swimming micro-organisms, hydrogels, LCEs, inflatables, martensitic films etc., see [18,10,67,43,82,62,4,49,60]. Morphing of tubular structures is discussed, in particular, in [66,70,71].…”

“…This strategy of hierarchical texturing of the active distortion field is useful to enlarge the palette of available active distortions. In nematic LCEs, for example, biaxial active distortions can be obtained by zig-zag textures of the nematic director which, at the microscopic scale, can only produce uniaxial active distortions as in (12), see [49].…”

Reprogrammable Soft Robot Actuation by Synergistic Magnetic and Light Fields

“…Programmable and reprogrammable morphing is investigated with much improved actuation performance. [21][22][23][24] For instance, microgratings/grooves are introduced to polymer-/ carbon-based actuators through mask-assisted filtration, UV lithography, and so on. [25][26][27] As a typical example, Wu et…”