Large deflection analysis of space frames

Abstract

Abstract A nonlinear finite element procedure for large deflection analysis of three dimensional frames is presented in this paper. On the basis of the beam‐column approach, the convected coordinate system is used in each element to separate the rigid‐body motions from the local deformations. In the derivation of the nonlinear stiffness matrix for the beam‐column element, the element axial shortening due to bowing is taken into account. With reference to a slightly deformed position of the beam column, the linearized coordinate transformation coefficients of the first and second orders are found and expressed explicitly by the member orientation matrix. The Newton‐Raphson method of iteration is adopted for solving the linearized system equation. Several selected examples are studied in detail. The numerical results indicate that the proposed procedure can be accurately and efficiently used to handle space frame problems with laige displacements and large rotations.