Design and Evaluation of Compliant Hinges For Deployable Thick Origami Structures

Origami models are often idealized by discrete folding of zero-thickness sheets; however, the sheet thickness and the elastic limit of the material cannot be ignored in engineering practice. One solution for realizing thickness is the compliant hinge, which realizes the folding deformation in the elastic range of the material by replacing the crease line with a wide deformation zone where the compliant structure is installed. However, the compliant hinge has several limitations. First, it cannot maintain the center of rotation (CoR) between panels during the folding motion. This makes origami structures with interior vertices not transformable because the crease lines are no longer concurrent. Second, the play caused by the wide deformation zone increases the degree of freedom of the origami structure, leading to instability. To solve these problems, we propose three types of new compliant hinges. We provide two evaluation methods: the play is evaluated using eigenvalue analysis, and the change CoR under unideal load conditions is evaluated using FEM analysis.