Earwig wing-inspired bistable origami: non-Euclidean units with soft joints

Area of Science:

• Mechanics of Materials
• Bioinspired Engineering
• Origami Engineering

Background:

• Origami structures can achieve multiple stable configurations, but control remains difficult.
• Insects like the earwig use non-Euclidean folding principles for compact storage and rapid deployment.
• Understanding bioinspired folding mechanisms is key to designing advanced materials.

Purpose of the Study:

• To investigate the bistable and multi-stable behavior of origami-inspired eggbox and saddle units.
• To explore how mirroring configurations influence stability and actuation in origami structures.
• To develop a systematic approach for programming multi-stability in origami-based designs.

Main Methods:

• Analytical energy modeling to understand folding mechanics.
• Experimental validation of predicted bistable and multi-stable behaviors.
• Investigation of single and two-unit origami assemblies with varying mirroring configurations.

Main Results:

• Bistability in single units is governed by a dominant folding (dihedral) angle, enabling single-input actuation.
• Two-unit assemblies exhibit synchronized snap-through (coupled bistability) or independent flipping (four stable states) based on mirroring.
• Incorporating deficit and redundant angles within a symmetric folding scheme allows programming of multi-stability.

Conclusions:

• A bioinspired strategy using geometric constraints and mirroring effectively programs multi-stability in origami structures.
• Control over synchronized and independent snap-through simplifies actuation and enables complex shape transformations.
• This approach offers broad applications in deployable structures, bioinspired soft robotics, and adaptive materials.