A simplified mechanical model of the crease in the flexible origami structures

Abstract

In origami structures, the deformation of shells are usually couples with the rotation of creases. In this study, a simplified mechanical model is established in order to obtain the equivalent stiffness of crease. The crease is assumed to be a curved sheet under pure bending, whose material is the same as that of the connected shells, then analyzed by the elastic/plastic plate theory.Employing the elastica theory and obtained rotational stiffness, simple origami with one-dimensional creases, are analyzed by the current theoretical model. Compared with corresponding finite element simulations, and published experimental data, the deformation profiles predicted by current analysis are confirmed to be accurate. Furthermore, the coupling effects between the rotation of creases and the bending of shells, are also investigated. It is found that the rotational stiffness k is highly related to the length of crease Lc, which only depends on the yield strain εY and the thickness of sheet t.