Engineered origami crease perforations for optimal mechanical performance and fatigue life

Perforating crease lines has been widely adopted as a practical method for designing thick engineering origami structures. Perforations inevitably reduce crease stiffness and thus affects the mechanical characteristics and fatigue performance of origami structures. It is therefore important to understand the effect of perforations on the performance of origami creases. The purpose of this study is to propose a perforated crease with desirable folding response and fatigue performance for engineering origami structures. Drawing on the literature on engineering origami, ten perforated creases are proposed, including single-and double-sided slots, oblong holes, elongated holes, moon holes, and barbell holes. Next, finite element analysis is used to assess their folding and unfolding responses, and to predict their fatigue lives combined with FE-SAFE. It is demonstrated that the crease with three rows of oblong holes is the optimal design, which has excellent mechanical characteristics and fatigue performance. A parametric analysis is then carried out to investigate the effect of sheet thickness, hole size, and holes arrangement on the performance of the optimal perforated crease. It is revealed that increasing sheet thickness, hole distance, or row distance exerts a positive effect on reaction forces, while increasing hole length or hole width produces a negative effect. Additionally, the fatigue life is severely reduced as sheet thickness or hole length increases, while it enhances with increasing hole width or hole distance. On the other hand, variations in row distance have an insignificant effect on the fatigue life. The parametric analysis presented in this study can provide guidance for the application of optimal perforated creases to engineering origami structures.