Towards designing a lockable self-folding origami

Abstract

Origami, an art of paper folding, has displayed its importance in engineering by emerging as a tool for building three dimensional (3D) structures out of patterned flat films. This has taken a step further through the introduction of self-folding origami. Recently, the term ‘locking’ has enrooted in the world of structures where origami stands out given its basic nature of folding. The possibility for an origami to self-fold and then lock itself in one of the metastable states can widen its scope in fields such as emergency shelters, robotics, and even the biomedical sector. For designing a self-folding lockable origami, special multi-stable designs have to be created. This work is a step towards it by offering a platform that can be used for quickly creating, testing, and identifying designs or design changes that can lead to multi-stable structures and how it can be exploited for possibly concluding on a lockable origami. The thesis starts with approximating an origami based on a reduced-order bar and hinge model and quantifying the key elements contributing to the deformation process. This is followed by the design of the master computational strategy connecting a simple CAD user input to the MATLAB code developed. For this, an in-depth discussion on extracting useful information, identifying panels, and discretizing them is done. A thorough theoretical narrative about calculating total mechanical energy and systematically solving for the equilibrium along with deriving relevant analytical expressions is presented. A separate section draws on the aspect of self-folding and showcases strategies for physically connecting external stimuli to folding. Here, a mathematical result is presented that deals with the curvatures obtained as a result ofkeeping a bilayer plate in a thermal stimulus which is used to conclude upon mechanisms for controlled self-folding. Finally, two examples have been shown that showcase the folding of a well-known Miura origami unit cell under external forces and the self-folding of a simple fold under heat.