Four dimensional printing with single and multi-component smart material structures

• Main Author: Feng, Xiaofan
• Other Authors: Li Lin
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/74965
• Institution: Nanyang Technological University

3D printing has been constantly evolving through decades since the invention in 1984. And it has been developed into 4D printing with the 4th dimension – time dimension from the static 3D printing. Printed objects are able to change their shapes when triggered by some external stimuli such as magnetic field, heat, optimal and moisture etc. In this project, shape memory polymers (VeroWhitePlus, DM 8510, DM 8520 and DM 8530 which have different compositions of materials) were used to study the recovery properties. Shape recovery tests have been carried out using a tensile machine and a temperature-controlling water tank. The recovery properties among four materials were obtained. Cross-folding, which means the structure is folded with two overlapping folds, has been investigated using the material that has the best recovery property. The smaller the geometric hinge thickness, the faster the shape recovery. The existence of a hole in the centre of the folding region helped to release the stress and prevent fracture. A sample with hinge thickness of 0.5 mm could be folded five times in average before fracture, while the maximum folding time for hinge with thickness of 0.3mm is seven in average before fracture. The hinge with thickness of 0.2mm was sensitive to the force and 0.1 mm lost structure strength that could not even be folded without cracking. A starfish and an umbrella shape were created using CAD software and were used to demonstrate the implementation of cross-folding using multi-component structure materials.