Folding and Deployment Simulation of Elastically Foldable Flat Arrays Using Refined Beam Finite Elements

This work explores the numerical simulation of the folding of complex structures consisting of pairs of Triangular Rollable and Collapsible (TRAC) longerons linked by transverse battens and parallel hinges. The analysis uses the Carrera Unified Formulation (CUF), which divides the three-dimensional displacement field of the structure into axial and cross-sectional terms, enabling one-dimensional beam finite elements to be used without sacrificing accuracy. Higherorder CUF models capture cross-sectional deformation through nine-point Lagrange expansions, extending through the whole structure. Thus, the numerical model of a complete structure consists of a single beam. An implicit quasi-static scheme, coupling Newton–Raphson iterations with displacement control is used across all analyses. Contact between the longerons is represented by nonlinear spring elements assigned to prescribed pairs of nodes.