Tailoring stiffness of deployable origami structures

deployable structures;mechanics of origami;scalable properties of origami;structural analysis of origami;bar and hinge model;origami tubes;zipper coupled tubes;thin sheet assemblages;cellular assemblages;reconfigurable systems;deployable arches and roofs;tunable metamaterials;polygonal tubes;curved origami tubes;variable cross-section tubes;programmable structures and materials

Filipov, Evgueni T

关键词: deployable structures;    mechanics of origami;    scalable properties of origami;    structural analysis of origami;    bar and hinge model;    origami tubes;    zipper coupled tubes;    thin sheet assemblages;    cellular assemblages;    reconfigurable systems;    deployable arches and roofs;    tunable metamaterials;    polygonal tubes;    curved origami tubes;    variable cross-section tubes;    programmable structures and materials;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/95597/FILIPOV-DISSERTATION-2016.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Origami has gained popularity in science and engineering because a compactly stowed system can be folded into a transformable 3D structure with increased functionality. Origami can also be reconfigured and programmed to change shape, function, and mechanical properties. In this thesis, we explore origami from structural and stiffness perspectives, and in particular we study how geometry affects origami behavior and characteristics. Understanding origami from a structural standpoint can allow for conceptualizing and designing feasible applications in all scales and disciplines of engineering. We improve, verify, and test a bar and hinge model that can analyze the elastic stiffness, and estimate deformed shapes of origami. The model simulates three distinct behaviors: stretching and shearing of thin sheet panels; bending of the flat panels; and bending along prescribed fold lines. We explore the influence of panel geometry on origami stiffness, and provide a study on fold line stiffness characteristics. The model formulation incorporates material characteristics and provides scalable, and isotopic behavior. It is useful for practical problems such as optimization and parametrization of geometric origami variations. We explore the stiffness of tubular origami structures based on the Miura-ori folding pattern. A unique orientation for zipper coupling of rigidly foldable origami tubes substantially increases stiffness in higher order modes and permits only one flexible motion through which the structure can deploy. Deployment is permitted by localized bending along folds lines, however other deformations are over-constrained and engage the origami sheets in tension and compression. Furthermore, we couple compatible origami tubes into a variety of cellular assemblages that can enhance mechanical characteristics and geometric versatility. Practical applications such as deployable slabs, roofs, and arches are also explored.Finally, we introduce origami tubes with polygonal cross-sections that can reconfigure into numerous geometries. The tubular structures satisfy the mathematical definitions for flat and rigid foldability, meaning that they can fully unfold from a flattened state with deformations occurring only at the fold lines. From a global viewpoint, the tubes do not need to be straight, and can be constructed to follow a non-linear curved line when deployed. From a local viewpoint, their cross-sections and kinematics can be reprogrammed by changing the direction of folding at some folds.