Folding pristine paper to an origami structure – materially and geometrically nonlinear finite element analysis

Cellulose-sheet-based origami packaging structures represent a promising solution for advancing environmental sustainability while meeting the growing demand for high-performance, functional, and personalized packaging. While significant progress has been made in modeling the mechanics and transformations of origami with pre-defined fold lines, as well as in the constitutive modeling of paper, there is limited research capturing the detailed physical transformation process from a pristine sheet to an origami structure. In packaging and converting, pre-treating fold lines is a common practice to define fold location and quality. However, leveraging the full range of manufacturing possibilities for origami requires a fundamental understanding of fold-line formation in non-trivial fold networks, where a pristine (no mechanical pre-treatment of creases) sheet is a starting point in folding. This study employs finite element modeling to systematically investigate the formation of Miura-ori-family-based structures in cellulose sheet materials with orthotropic, nonlinear constitutive behavior. The results reveal how tessellation parameters, material properties, and imperfections influence folding mechanics and the pristine formation of fold lines near fold intersection points. • Folding deformation of a pristine flat sheet to Miura-ori origami structure. • Pattern kinematics associated with the physical folding process. • Nonlinear calibrated orthotropic constitutive sheet material behaviour.