Folding simulation of TRAC longerons via unified one-dimensional finite elements

This paper proposes a simulation of the folding phase of TRAC deployable booms using refined one-dimensional finite elements in the framework of the Carrera Unified Formulation. The mathematical model involves standard beam finite elements placed along the length of the longeron, and Lagrange polynomials as expansion functions for the cross-sectional domain. The nonlinear governing equations are written recalling the principle of virtual work, and they are linearized using the Newton-Raphson scheme. The contact between the two flanges is simulated with linear spring which activate when pre-defined node pairs approach under a fixed tolerance. Two simulations are carried out, including or not the contact behavior, respectively. The results highlight the capability of the proposed model to deal with large displacements and contact between the ultra-thin flanges of the structure.