Reconfigurable origami structures

Thesis

This dissertation focuses on the kinematics of origami mechanisms and converting single degree of freedom (DOF) patterns into reconfigurable structures with two DOFs./p>

The presented kirigami method assumes introducing slits along creases of rigidly-foldable zero-thickness patterns. Before cutting, they usually have one motion driven by a single DOF that leads to only one final form. It makes such shapes a good choice for easily-controlled deployable systems. However, the lack of alternative motions is unfavourable for multifunctional applications requiring reconfigurability. The presented cutting of origami hinges equals removing kinematic joints. Such modifications may bring extra DOFs allowing reconfigurability. The fundamental building blocks used to construct the reconfigurable patterns are two-DOF spatial 8R linkages resulting from two-crease-long slits./p>

First, the thesis assumes regular multiplication of such slits inside rigid origami version of Miura-ori. As a result, it produces rigid kirigami variants of the pattern that are reconfigurable. They can exhibit new motions paths and numerous alternative shapes and folded forms. During particular reconfigurations, the assembly even displays metamorphic and kinematotropic behaviour, which increases available shapes. However, the above is possible with multiple DOFs, whose number increases as the pattern gets large, making its control challenging. /p>

Therefore, in its second part, the thesis uses an alternative approach to multiplying the slits that includes a step-wise kinematic analysis to control the final DOF number. A target value of two DOFs is assumed, which provides a reasonable balance between reconfiguration choices and simple manipulation by only two inputs. As a result, a two-DOF rigid kirigami Miura-ori is obtained with an orderly symmetric slit layout. It retains the traditional in-plane folding and additionally can reconfigure into bent-like shapes with out-of-plane curvatures. Previously, such forms were impossible without deforming facets or redesigning the crease pattern./p>

Finally, the third part applies the identified slit arrangements to other one-DOF rigid origami, i.e. Eggbox, Anisotropic Miura, Arc-Miura and Arc patterns. Their reconfigurable two-DOF versions are found, and their models manufactured. Moreover, many intriguing research directions emerge throughout the project. Nevertheless, the identified kirigami structures already provide an exciting platform for novel reconfigurable applications in various fields.

Authors: Portka, MA

• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: reconfigurable mechanism; rigid origami; kirigami structure; cutting; linkage analysis; degrees of freedom; kinematics
• Subjects: Shapeshifting; Kinematics; Structural analysis (Engineering); Expandable space structures; Smart structures; Kinematic geometry; Origami