Shape-shifting panel from 3D printed undulated ribbon lattice. (January 2021)

• Record Type: Journal Article
• Authors: Agnelli, Filippo; Tricarico, Michele; Constantinescu, Andrei
• Is Part Of: Extreme mechanics letters. Volume 42(2021)
• Publication Date: 2021-01
• Subjects: 3D printing -- Metamaterial -- Shape shifting -- Panels -- Undulated ribbons; Mechanics -- Periodicals; Mechanics, Applied -- Periodicals; Mechanics; Electronic journals; Periodicals; 531.05
• DOI: 10.1016/j.eml.2020.101089
• Languages: English
• ISSNs: 2352-4316

Abstract

Abstract: Materials that change their shape in response to external stimuli open up new prospects for efficient and versatile design and shaping of three-dimensional objects. Here, we present a novel class of micro-structures exhibiting an extension-bending coupling (EBC) effect, that can be harnessed as an elementary building block for shape-shifting panels. They are built with a single material as a network of undulated ribbons. The deformations mechanisms of both single and connected undulated ribbons are analysed using the finite element method to explain the main features of the EBC mechanism. For a particular micro-structure of the proposed class, the elastic response is investigated both under small strain assumption combining two-scale homogenization with Kirchhoff–Love plate theory, and at finite strains relying on numerical analysis. The range of achievable EBC ratio is then assessed with respect to the geometric parameters of the unit cell. Patterned specimens are manufactured using a commercial FFF Ultimaker 3D printer and are mechanically tested at finite strain up to 20%. The displacement measured by point tracking match the predictions from the finite element simulations and indicate that the structure maintain its properties at finite strain. Moreover, a tensile test load with point-like boundary is proposed to highlight exceptional out of plane displacement. The proposed ribbon based architectures can be combined with active materials for the actuation of shape shifting structures, like soft robots, control systems and power devices. Graphical abstract: Highlights: A novel micro-structure with extension-bending coupling effect is designed and fabricated. Ribbon lattice are easy to design and fabricate, and offer a wide range of tunable properties. The deformation modes and deformation mechanisms of the unit cells are investigated. The design concept provides a framework to be harnessed in morphing and deployable structures for a wide range of scales.