3D printed active origami with complicated folding patterns

3D printed active composites (PACs) are a new concept in active composite design and manufacturing where one or several active materials are used as fiber materials to create active shape changing composites that are determined by the design of fibers. Recent advances in multi-material 3D printing have enabled the rapid realization of these designs, many of which would not be possible without 3D printing. In addition, the integration of active materials with 3D printing also permits the novel concept of 4D printing, where the shape of an object can change after 3D printing. In the past, using printed active composites to create origami structures was demonstrated but was limited to simple folding patterns. In this paper, we study the relationship among folding angle, fiber orientation, and applied load during programming, in order to find the optimized fiber arrangement and loading directions for complicated folding patterns. Both experiments and finite element1 simulations were performed to optimize the fiber orientations in PAC in order to achieve the desired shape change, and good agreement was achieved. FEA was then used to help the design for some complicated, self-folding, active origami structures-including a miura-ori pattern, a table, a sailboat and a crane—in which the folding occurs in different directions. The successful implementation of these complicated patterns demonstrates the capability of using printed active composites for very complicated self-folding origami designs.