Truss behavior considering geometric nonlinearity and elastoplastic constitutive relation with Damage

Matheus Lopes Peres¹; Deane Roehl¹

¹ PUC - Rio

doi:10.20906/CPS/CILAMCE2017-0879

Resumo

Trusses are structures widely used in civil construction mainly because it is a very light solution compared to other types of structures. On the other hand, its behavior when taken into account the geometric and / or material nonlinearities may present complex phenomena. It is in this context that this paper proposes to make a nonlinear analysis of the behavior of a Mises truss using the Finite Element Method. In the study, geometric and physical nonlinearities were considered, observing their behavior through their equilibrium trajectory. Geometric non-linearity was considered using the Green-Lagrange deformations and the equilibrium in the deformed configuration, using a Total Lagrangian formulation. Physical nonlinearities are characterized by an elastoplastic behavior with material damage. The method used to solve the system of non-linear equilibrium equations was the Newton-Raphson method using different types of control, such as load control, displacement control and arc length control. A parametric analysis of the structure identifies the most appropriate controls for each type of dominant nonlinearity. It was verified that the effect that manifests first along the equilibrium trajectory, the plastic hardening or the damage, will influence in the classification of the structure as to its ductile or fragile behavior, and consequently in the choice of the control that allows to reproduce the equilibrium trajectory.

Palavras-chave: Finite Elements; Plasticity; Continuous Damage Mechanics; Geometric Nonlinearity