Static bearing capacity analysis of angle steel members incorporating simultaneous geometric and material nonlinearities

Owing to the absence of robust analytical theoretical analysis methods, the elastic-plastic ultimate bearing capacity of angle steel section components in transmission tower is usually addressed by finite element simulation and experiments. In this work, the elastic stiffness matrix that accounts for the deformation of the element was derived using fifth-order interpolation function. The dual nonlinear static analysis method was proposed by combining the material nonlinear plastic stiffness matrix and geometrical nonlinear stiffness matrix. The material nonlinear plastic stiffness matrix of beam element with angle section was derived through the yield surface and the concentrated plastic hinge models, and the geometrical nonlinear stiffness matrix of angle section was derived by the rigid-body criterion. The accuracy and effectiveness of the analysis method proposed in this work were verified through various examples, and the research results can provide theoretical references for the analysis and calibration of the mechanical properties of transmission tower.