4D printing of self-folding materials

This work is part of the project, Thermorph: democratizing 4D printing of self-folding materials and interfaces, to verify the hypothesis on the material mechanism of a self-folding rose model. Self-folding material has been mentioned as an effective way to increase the speed of manufacturing 3D objects but challenges exist either these systems require material synthesized by experts in material science or material is not generated enough to be used to create certain arbitrary 3D geometries. However, with Thermorph, we created a self-folding material that is printed flat initially and self-folds into a 3D under heat treatment by using the shape memory thermoplastic, PLA and TPU, and their capability of changing shape upon temperature changes. Meanwhile, the folding angle can be controlled by printing speed and the width of the actuators from the experiment results. Based on the successful self-folding rose modeling, we created and simulated this rose with four layers by Abaqus and compared with the realistic result to verify the prediction of folding angles.  In this work, we created the user materials to mimic the PLA and TPU, varied by printing angles and speed. Using explicit C3D8R element and thermal treatment trigger the self-folding process which allow the fold of the vertical stem part in a spiral direction, followed by the flipping motion of each petal.