Resposta dinâmica de pórticos Planos com ligações semirrígidas não lineares

Abstract

In the design of high performance structures such as buildings subjected to dynamic loads and earthquakes, the dynamic analysis with physical and geometric nonlinearities is commonly used with Finite Element Method (FEM). In this context, there are some structures with devices for vibration controlling as well as semi-rigid connections. However, in order to perform a more realistic structural analysis, it is necessary to take into account these aspects in projects. Thus the aim of this paper is to evaluate an alternative way of including viscoelastic connections in 2D framed structures with nonlinear behavior through a formulation that uses nodal positions instead of displacements as unknowns of the problem, called positional formulation. The Reissner kinematics is applied to consider the effects of shear and the Newton-Raphson iterative algorithm is adopted to solve the nonlinear problem. Also, the Kelvin-Voigt rheological model to represent the viscoelastic behavior of the connections. The validation of the implemented code was performed by solving numerical examples from the literature. For the analyzed structures, it was verified that the shear deformations together with the semi-rigid connections, whether linear or not, significantly modify the dynamic behavior of the plane frames.