Analysis of Dynamic Stability of Frame Columns under The Effect of Concentrated Mass and Inherent Damping by Finite Element Method

Articles in Press

Document Type : Research Article

Authors

1 Structural Engineering, Department of Civil Engineering, Imam Khomeini International University, Qazvin, Iran

2 Assistant professor, Faculty of Engineering and Technology, Department of Civil Engineering, Imam Khomeini International University, Qazvin, Iran

10.22060/ceej.2025.22319.7950

Abstract

Analysis of stability in columns as the main structural member has a special place in engineering research. In most of the past research, generally, researchers have studied the static buckling in columns (prismatic or non-prismatic) in (building frames or industrial beams). Static load capacity only expresses the static critical load capacity of members under gravity load. For the safe design of the structure, it is necessary to check the dynamic stability of the columns in the building frames under the vertical load of an earthquake. In this article, in a comprehensive model, the combined effect of inherent damping, floor mass and vertical earthquake load on the dynamic stability of columns in unrestrained moment frames is investigated. In fact, the proposed method is a combination of Julian-Lawrence static modeling and Bolotin dynamic modeling to consider the dynamic effects in the frame columns based on the finite element method. In this study, the shape function is estimated using the finite element method with Hermitian third degree interpolation functions for 50 components. The results show that the inherent damping, concentrated mass and rotational stiffness of semi-rigid joints have a significant effect on the resonance frequency, effective length and dimensionless dynamic load factor. With the increase in inherent damping, rotational stiffness and concentrated mass, the graph of effective length changes is shifted to the left side of the excitation frequency axis. Considering the effects of inherent damping and concentrated mass in the modeling, 7% and 81%, respectively, affect the resonance frequency changes.

Keywords

Main Subjects

Amirkabir Journal of Civil Engineering

Articles in Press, Accepted Manuscript
Available Online from 03 July 2025

Files

Share

How to cite

Statistics