Nonlinear inelastic analysis of space frames

In this paper, a fiber beam–column element which considers both geometric and material nonlinearities is presented. The geometric nonlinearities are captured using stability functions obtained from the exact stability solution of a beam–column subjected to axial force and bending moments. The material nonlinearities are included by tracing the uniaxial stress–strain relationship of each fiber on the cross sections. The nonlinear equilibrium equations are solved using an incremental iterative scheme based on the generalized displacement control method. Using only one element per member in structure modeling, the nonlinear responses predicted by the proposed element compare well with those given by commercial finite element packages and other available results. Numerical examples are presented to verify the accuracy and efficiency of the proposed element.

Research highlights
► A fiber element is proposed for the nonlinear inelastic analysis of space frames.
► A computer program is developed for the nonlinear analysis of frames.
► The proposed program is proved to be an efficient tool for the frame analysis.