Educational tool for analysis of steel frames with semi-rigid connections

Resumo

The article describes the implementation in Ftool of semi-rigid connections with nonlinear behavior of
the moment-rotation relationship. The main objective is to describe the extension of the program's graphical
interface and its use to demonstrate the behavior of steel frames with semi-rigid nonlinear connections. Although
it is possible to couple the physical nonlinearity of the connection with geometric nonlinear analysis, the article
deals only with physical nonlinearity. The semi-rigid connection is modeled using a finite element with two nodes
with a stiffness matrix that relates the relative rotation between the two nodes and the moment in the connection.
Nonlinear behavior is provided by multi-linear curves relating moment to rotation. The monitoring of the
equilibrium trajectory of the structure with nonlinear behavior is performed in an incremental-iterative manner
using several types of classical algorithms in the literature. It is also possible to show structure buckling and
vibration modes considering the linear behavior of the semi-rigid connection.