Design and 3D printing of reconfigurable strucutures

Abstract

A Bi-Stable Structure refers to a structure capable to maintaining 2 different states. Mechanically, the structure is able to maintain 2 different shapes at different states. This is due to the Pre-Stressed Limbs/Joints located within the structure. Upon encountering an external force, the structure will be forced to ‘snap’ to the other state. A common example of this is a Snap Bracelet. In the first state, the bracelet can maintain its straight and stiff shape. However, when a force is applied to the curved surface of the bracelet, the bracelet will snap into the 2nd shape, wrapping itself around the wrist of the user. The proposed idea was to make use of a ‘Web’ of Bi-Stable Structure to form a shoe. In order to solve this challenge, a small section of the shoe is studied and experimented. The goal is to create a small section capable of maintaining this shape at any one time and another when force is applied. These sections will then be formed together with multiple other sections in order to form the shoe. 3D Printing the section was proposed. It allows for the section to be quickly created and in the shape the user need for testing. Material used for testing was ABS and 3D printed by a supplier. Result of the printed structure was not desirable. The main factor was that due to the structure being printed in 1 piece, there was not any Pre-Stressed Limbs/Joints in the structure. The resulting structure could not maintain the 2nd Shape. For Future Testing, it would be recommended to print the limbs of the structure with joints shaped like a rivet. This way, there will be Pre-Stressed formed on the structure. Furthermore, it will be recommended that the limbs are stiff and not able to bend too easily. This way, there will be a reaction force forcing the structure to snap to the various states.