LARGE DEFORMATION ANALYSIS OF ELASTIC SPACE FRAMES

A method for large deformation and stability analysis of elastic space frames is presented. The method is based on an Eulerian formulation, which takes into consideration the effects of large joint translations and rotations. Local member force-deformation relationships are based on the beam-column approach, and the changes in member chord lengths caused by axial strain and flexural bowing are taken into account. The effect of axial force on member torsional stiffness is included in the analysis. The method employs an orthogonal joint rotation matrix to determine the orientation matrices of the joints in the deformed configuration of the structure. A procedure for determining the deformed orientations of joints and members of space frames is described in detail, and the computational aspects of the analytical procedure, with emphasis on the advantages and limitations of some simplifying approximations, are examined. Numerical solutions are presented for four structures, which indicate that the method of analvsis is highly accurate in predicting large deformation responses of structures.