- The paper investigates the multistability of planar origami structures, starting with degree-4 vertices and exploring their multiple configuration branches and stable states.
- By modeling vertices with torsional springs and analyzing the energy landscape, the study reveals that degree-4 vertices can exhibit up to six stable states depending on geometric and spring parameters.
- The research proposes a method to extend these multistable properties to large-scale metasheets by tessellating arbitrary 4-vertices, enabling applications in reconfigurable materials.
Origami-inspired mechanical metamaterials have recently garnered significant attention due to their potential for functional versatility and unique mechanical properties, such as negative Poisson’s ratios, vanishing shear moduli, and switchable multistability. This paper investigates the multistable behaviors emerging from planar origami structures, focusing on degree-4 vertices and their implications for creating origami metasheets.
The authors begin by dissecting the fundamental properties of degree-4 vertices, identifying their configuration space as comprising multiple branches, with at least two distinct ones meeting at a flat state. This multibranch nature implies that generic vertices exhibit bistability, although the paper reveals that up to five stable states can occur due to nonlinear branching. The research details how these branches manifest, influenced by collinear folds or geometric symmetries, which may increase stable states to as many as six.
A central aspect of the paper is the exploration of the energy landscape through modeling with torsional springs, which provides insight into the stability conditions across these branches. By parametrizing the system with one folding angle, the energy profile exhibits complexities leading to multiple minima depending on parameters such as the rest angles and spring constants. This intricate energy topology underscores the potential for tuning and designing multistable states in origami materials. Notably, the occurrence of rare pentastable states and the possibility for six stable states hinge on precise geometric and spring configurations.
In advancing this theoretical framework, the authors propose a method to create multistable metasheets by tessellating arbitrary 4-vertices. This construction method extends bistabilities and other multistable phenomena of individual vertices into sheet-wide characteristics, maintaining the multistability properties within a tessellated plane. The paper illustrates examples where distinct stable states result in visually and functionally different macroscale deformations of the metasheets, promising significant applicability in areas such as reconfigurable optics and soft robotics.
The theoretical implications of this research are significant in that they add depth to the understanding of origami-related metamaterials as programmable materials, capable of complex, reconfigurable mechanical responses. Future directions are abundant, ranging from the exploration of non-planar geometries to more complex vertex systems with increased degrees of freedom, posing questions about the generalizability of these findings to even more complex folding structures. Additionally, advanced design methodologies that incorporate computational approaches could enable the discovery of yet untapped capabilities in the programmable mechanical behavior of origami metamaterials.
This detailed investigation offers substantial value to researchers focused on metamaterials, mechanical design, and deployed origami, providing a robust framework for future explorations into the profundity of mechanical multistability in engineered origami structures.
