Numerical analysis of circular hollow section bar with stiffened flattened ends

Resumo

Circular hollow sections are usually used in long-span roof truss systems due to the advantages they offer. One of the typology for connecting elements in such structures involves the flattening of bar ends, in order to provide a simpler and more economical connection. A new flattening typology called stiffened flattening is proposed, characterized by a non-flat geometry, with the creation of stiffeners in the lateral edges of the bar flattened ends. A theoretical, numerical and experimental study was carried out on the behavior of a plane truss composed of circular hollow sections, in which diagonal bars have stiffened flattening ends. The diagonal connecting system with the chord members uses connecting plates. The plates are welded to the chords and the diagonals are connected to latter through a single bolt. This work presents the numerical analysis of a circular hollow section bar with stiffened flattening ends subjected to compression. This is a study of the behavior of an isolated bar compressed from the truss, which corresponds to the most requested diagonal composed by circular hollow sections with stiffened flattening ends. The numerical analysis using finite elements method was developed through ANSYS software with the Parametric Design Language (APDL), in which parameters such as geometry, material, element type, definition of the finite element mesh, boundary conditions and application of compression loads are specified. A non-linear analysis was performed using shell element on the bar with stiffened flattened ends. The numerical analysis result satisfactorily represented the structural behavior of the isolated circular hollow section bar with stiffened flattening ends. It was possible to observe the buckling effect of the compressed circular hollow section bar and the effect of the axial load eccentricity due to the stiffened flattening of bar ends.