A modal identification method for buckling analysis of thin-walled lipped channel columns

Abstract

This work deals with modal identification of cold-formed lipped channels subject to uniform compression. A literature review of the subject revealed that the majority of modal decomposition/identification methods are aimed at numerical results of columns. Thus, a modal identification method capable of handling equally numerical and experimental results is developed and presented. For the development of the method, new shape functions for anti-symmetric distortional and local modes of lipped channel columns are derived. In order to validate the proposed method, results are compared with those obtained with Generalised Beam Theory (GBT) modal identification for ten numerical columns found in literature. The proposed method is then applied to six experimental results of compressive tests carried out at Laboratory of Structures and Materials (COPPE/UFRJ). The results of the method show good agreement with the experimental results and allow the reconstruction of the entire deformed shape of the column as well as the reconstruction of the individual contributions from each main buckling mode developed during tests.