A Parametric Postbuckling Analysis of an Asymmetric Two-Bar Frame

Abstract

The modified potential energy approach of flexurally elastic, axially, and shear undeformable beams is emplo:yed to investigate the buckling and (asymmetric) postbuckling behavior of the two-bar frame which was experimentally tested by Roorda in 1965. Following a Koiter-type energy approach, a suitable perturbation formulation is derived from a "hybrid" functional which is obtained by adding to the potential energy certain extra terms which account for the energy associated with the internal joint forces acting on the beam. In this way the nonlinear constraints expressing continuity of displacement across the joints are accommodated by introducing jointforces acting as Lagrangian multipliers. The inherent simplicity of the model herein proposed allows a thorough parametric analysis to be performed without undue complications up to and including fourth-order terms. The general trend compares favorably with the experimental results. Previous analytical results limited to a third-order analysis are in agreement with the present results. 43i5

Nonlinear Generalized Beam Theory for open thin-walled members

“…In the framework of GBT, the three-dimensional (3D) elasticity problem is transformed, via a semi-variational approach, into a simpler onedimensional (1D) problem, as in the compact beam theory (e.g. [5], [6]). Semi-variational methods have been described from a general point of view in several classic books (e.g.…”

Influência Da Interação Não-Linear Entre Flexão E Deslocamento Lateral Na Instabilidade Estática E Dinâmica De Um Modelo Conceitual De Coluna

“…Os pórticos em L são conhecidos na literatura como pórticos de Roorda, que analisou experimentalmente o comportamento pós-crítico desta estrutura (Roorda, 1965). Koiter (1967), Roorda e Chilver (1970), Rizzi et al (1980) (1985), Hunt et al (1986), Gioncu (1994aGioncu ( , 1994b, Gioncu et al (1992); Dubina e Ungureanu (2014) e Hancock (2017), dentre outros.…”