Finite element method for stability and vibration （稳定和振动的有限元方法）.pdf

Finite element method for stability and vibration analyses of thin- walled beams with arbitrary cross-section *M. Soltani1), B. Asgarian2), and F. Mohri3) 1) ,2) Civil Engineering Faculty, K.N.Toosi university of Technology, Tehran, Iran 1) msoltani2@ 3) Université de Lorraine, Laboratoire dEtude des Microstructures et de Mécanique des Matériaux (LEM3), Metz. France ABSTRACT In this paper, a generalized numerical and theoretical method is presented for the free vibration and stability analyses of tapered thin-walled beams with non-symmetric cross-section. The total potential energy is derived for an elastic behavior from the strain energy, the kinetic energy and work of the applied loads. Free vibration is considered in presence of harmonic excitations. The effects of the initial stresses and load eccentricities are also considered in the study. The governing equilibrium equations, motion equations and the associated boundary conditions are determined from the stationary condition. …… 1. INTRODUCTION The use of thin-walled beams with I, Z and C cross sections has been increasing in many steel constructions due to their ability to utilize structural material more efficiently and optimize the distribution of weight. Flexural-torsional stability and vibration analyses are important topics in the design of these structures and research of accurate models has interested many researchers over the world from the last mid century until now. Since the early works of (Timoshenko 1961) and (Vlasov 1959) there have been extensive investigations on the elastic flexural-torsional buckling behavior of thin walled be