Experimental Evaluation of Tension and Shear Responses of Material Discontinuities in Origami-Based Sheet Metal Bending

Origami-based sheet metal (OSM) bending uses the origami concept to form a three-dimensional (3D) structures from a two-dimensional (2D) sheet by a series of bending operation. The OSM bending relies on a material discontinuity (MD) to perform the bending operation where the MDs are subjected to tension and shear load. Even though the OSM bending is a process that is simple, cost-effective, and easy to integrate into mass production, the understanding of the OSM bending mechanics is limiting its wide application. Particularly, the deformation behavior of MDs under tension and shear load remains unknown. Hence, this work investigates the response of MDs to these loads using the standard tension and shear tests. From the tests, critical values for two different ductile fracture criteria (DFC) are determined, and the possibility of a failure occurring in OSM bending is predicted. Results show that the load-bearing capability of the MDs is related to change in the effective cross-section area of a MD. Simple tension and shear tests can provide a simple procedure to predict failure in OSM bending. The impact of self-contact occurred under shear load influences maximum shear force and accuracy of failure prediction.