Abstract
Compared to ideal purely rotational creases, the introduction of rotational stiffness in the creases of origami/kirigami units inevitably alters the shape transformation process due to the interaction between the creases and the panels. The unfolding process of creased units with crease rotational stiffness involves two stages: the flattening process and the over-tensioning process. This paper focuses on the impact of crease rotational stiffness on the uniform stretching process of creased units of different modes and sizes. During the flattening process, the strain energy distribution for creased units in straight and inclined modes is analyzed, revealing the influence of geometric parameters through the use of a scale parameter, which can provide references for the design of creased units. In the over-tensioning process, the suppression effect of low over-tension strain levels on out-of-plane residual deformation in the flattened state of the creased units is systematically explained, with a significant influence from panel width. Additionally, it is discovered and explained that over-tension strain can lead to the overall rotation of certain areas in inclined creased units. Although this paper starts with a simple creased unit and overlooks the interactions between panels, the coupling deformation behavior between the crease and the panels during the tensioning process can still provide valuable insights for the deformation analysis of more intricate origami/kirigami structures.
