Abstract

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Title:: Accurate Analysis Method on Tangent Stiffness Matrix for Space Beam Element

Keywords:: space beam element; tangent stiffness matrix; space frame; nonlinear buckling; elastoplastic buckling

Abstract:: In order to effectively conduct the postbuckling analysis for space frame, a new accurate analysis method for the tangent stiffness matrix of space beam element was proposed. Firstly, the incremental force and displacement of the member ends for space beam element was established using direct equilibrium method, and then derivation of the memberend force was determined with regard to the memberend displacement according to the matrix differentiation theory and the increment of memberend displacement of the derivation expression was set equal to zero, so that the tangent stiffness matrix for space beam element was obtained. The postbuckling analyses for a sixstorey space frame and a twentystorey frame were done. The results show that the present tangent stiffness matrix for space beam element has enough precision, and can be applied to the postbuckling analysis for large space frame.