Researchers Make Strong, 3D Printed Expandable Origami Structures for Engineering Applications

A collaborative team of researchers from the Georgia Institute of Technology, the Beijing Institute of Technology, and Peking University are using 3D printing to directly build reconfigurable origami assemblages that can expand and fold. But even better, the 3D printed structures also have enough load-bearing capability and strength to be used in engineering applications.

In a paper published in Soft Matters, titled “3D printing of complex origami assemblages for reconfigurable structures,” the researchers explained how they used digital light processing (DLP) 3D printing to fabricate structures with hollow features.

With this method, far less support material is required for 3D printing hollow features, and softer materials, necessary for flexible structures, can be used.

The abstract of the paper reads, “Origami engineering principles have recently been applied to a wide range of applications, including soft robots, stretchable electronics, and mechanical metamaterials. In order to achieve the 3D nature of engineered structures (e.g. load-bearing capacity) and capture the desired kinematics (e.g., foldability), many origami-inspired engineering designs are assembled from smaller parts and often require binding agents or additional elements for connection. Attempts at direct fabrication of 3D origami structures have been limited by available fabrication technologies and materials. Here, we propose a new method to directly 3D print origami assemblages (that mimic the behavior of their paper counterparts) with acceptable strength and load-bearing capacity for engineering applications. Our approach introduces hinge-panel elements, where the hinge regions are designed with finite thickness and length. The geometrical design of these hinge-panels, informed by both experimental and theoretical analysis, provides the desired mechanical behavior. In order to ensure foldability and repeatability, a novel photocurable elastomer system is developed and the designs are fabricated using digital light processing-based 3D printing technology. Various origami assemblages are produced to demonstrate the design flexibility and fabrication efficiency offered by our 3D printing method for origami structures with enhanced load bearing capacity and selective deformation modes.”

Many 3D printed structures with unique properties have been inspired by origami, opening up applications in soft robotics and self-folding structures. While most origami structures mean thin sheets being joined together with binding elements like glue, the research team found a way to make several 3D assemblies in one step, without needing to connect smaller parts together. The team, led by Zeang Zhao, developed a new polymer and used geometrical design to move towards using origami for engineering structures.

To build the origami, the team developed a novel new elastomer, which makes it possible for the structure to be created from a single component. The elastic polymer material can be 3D printed at room temperature and set with UV light, which forms a soft, foldable material that can be stretched up to 100%. This material was used for the whole 3D assembly. DLP 3D printing was used to build structures, made up of various combinations of individual units of origami, without requiring any extra assembly steps.

By altering how each origami unit is connected, the structures can be designed to have different load-bearing capabilities: vitally important for applications in engineering. One of the test structures was even able to support a load that weighed 100 times more than the structure itself did. But here’s the really interesting part – just by rearranging the same individual units in a different way, the team was able to build a bridge that, under the same heavy load, would fold flat.

The structures were designed with thick panels, which were separated by hinges not unlike the creases in a piece of paper. The hinges made it possible for the angle between the panels to vary between 0° and 90°. Hinge thickness is important for a structure’s mechanical properties: if it’s too thick, it won’t fold well, while if it’s too thin, it might not be able to support the structure’s weight. In addition, the researchers made sure that the high strain and stress the structures experienced during folding was localized specifically to the hinges, so the panels would not end up deformed.

Co-authors of the paper are Zhao, Xiao Kuang, Jiangtao Wu, Qiang Zhang, Glaucio H. Paulino, H. Jerry Qi, and Daining Fang.

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[Source: Physics World]