Analysis of Steel Frame in ANSYS

Abstract: In the modal analysis of plane frames, the primary objective is to determine the natural frequencies and associated mode shapes of the structure under free vibration. Dynamic analysis of frames requires the inclusion of axial effects in both the stiffness and mass matrices, along with coordinate transformation from local to global systems. Modal analysis facilitates the evaluation of vibration characteristics through the computation of eigenvalues and eigenvectors, which represent frequencies and mode shapes respectively. This study aims to investigate the vibration behavior, frequency, and mode shape of plane frames using the direct stiffness method. The stiffness and mass matrices are formulated, and computational models are developed using ANSYS and MATLAB codes. Comparative results are presented to validate the methodology and highlight the accuracy of the developed formulations.

Keywords: Steel plane frames, ANSYS, Finite element analysis (FEM).