Programming complex shapes in thin nematic elastomer and glass sheets

TL;DR

This paper introduces a key metric constraint governing shape change in nematic elastomer and glass sheets, demonstrating their potential for complex actuation through nonisometric origami and lifted surfaces.

Contribution

It formulates a fundamental metric constraint for shape programming in nematic sheets and explores its implications for designing complex 3D shapes.

Findings

The metric constraint enables complex shape programming.

Examples include nonisometric origami and lifted surfaces.

The constraint arises from energy minimization involving stretching, bending, and heterogeneity.

Abstract

Nematic elastomers and glasses are solids that display spontaneous distortion under external stimuli. Recent advances in the synthesis of sheets with controlled heterogeneities have enabled their actuation into non-trivial shapes with unprecedented energy density. Thus, these have emerged as powerful candidates for soft actuators. To further this potential, we introduce the key metric constraint which governs shape changing actuation in these sheets. We then highlight the richness of shapes amenable to this constraint through two broad classes of examples which we term nonisometric origami and lifted surfaces. Finally, we comment on the derivation of the metric constraint, which arises from energy minimization in the interplay of stretching, bending and heterogeneity in these sheets.