Nonlinear Computation of Shear Lag Effect of Box Beam

This paper presents an initial value solution of static equilibrium differential equations of thin-walled box beams considering shear lag, shear deformation and geometric nonlinear, which was used to establish the related element stiffness matrix, geometric stiffness matrix and equivalent nodal forces vector. So that the nonlinear analysis of thin-walled box beams is admitted into the program system of matrix-displacement method. The nonlinear equilibrium equation of thin-walled box beam element in the Lagrangian coordinates and its iteration expression were established, and in the computation the displacement-based convergence criterion was used to solve the problem.