LARGE ELASTIC-PLASTIC DEFORMATIONS OF SLENDER BEAMS - COROTATIONAL THEORY VS VONKARMAN THEORY

The consistent co-rotational beam formulation has been modified to inc lude inelastic deformation using a sublayer material model. An explici t tangent stiffness matrix for a non-conservative beam was consistentl y derived from the assumed beam kinematics. Several example problems w ere solved to verify the formulation and, subsequently, a comparative study was carried out to examine the validity of the von Karman theory in large deflection analysis. It is found that the presence of beam a xial constraint plays an important role on the performance of the von Karman approximation. In general, the von Karman formulation can provi de reasonable solutions to large deformation problems of extensional s tructures, but its performance becomes unsatisfactory for the inextens ional case even under relatively small deflections.