Spatial Buckling Analysis: a Comparison of Formulations

Abstract

A geometrical stiffness matrix for a spatial beam element is derived in detail using lineal Lagrangian interpolation of translations and rotations along the element. It is applied in linearized buckling analyses. For comparison with other geometric matrices derived with cubic Hermitina interpolations for transverse displacements, the same elastic stiffness matrix is used in the examples. It is concluded that both formulations lead to erroneaous results, and require similar corrections.