Análise da interação entre modos de flambagem local e distorcional em perfis de aço formados a frio com seção U enrijecido sob compressão axial

Abstract

The present work presents numerical results of finite elements (MEF) of coldformed steel lipped channel columns in axial compression using ANSYS commercial software. These columns are subject to instabilities modes called local, distortional and global buckling and they can interact with each other. These interactions can occur when two or three buckling modes manifest simultaneously, resulting in a complex phenomenon. The local-distorcional mode is one of the most important buckling interactions that need a large volume of study and hence is the central theme of this research project. The present work includes: (i) literature review of experimental and numerical research on L-D interaction, (ii) calibration of the FEM model based on comparison between numerical and experimental results, (iii) creation of two equations to deal with this phenomenon, called Pprop1-2 and Pprop3, (iv) validation of these two equations based on numerical and experimental results, (v) estimation of resistance factor of these two equations (vi) proposition of a continuous resistance surface. Based on the results, the ultimate compression load DSM equations (Pprop1-2 and Pprop3) have excellent results when compared to 54 experimental columns and more than 250 numerical columns and the resistance factor presents a very close result to the Brazilian Code (NBR 14762, 2010).