Analysis of thin-walled anisotropic frames by the direct stiffness method (Q675350)

The stiffness matrix for a one-dimensional beam element for use in a direct stiffness matrix method for analysing thin-walled anisotropic frames is presented. The stiffness matrices for two 2-nodes 12 degrees of freedom beam elements, one of which accounts for warping and anisotropic coupling only and is called a ``warping superelement'', and the other a ``non-warping element'', are developed numerically. The warping superelement is used in the region of the beam where warping is considered critical. The non-warping element is used outside of this critical region. Numerical examples of thin-walled space frame structure are presented to demonstrate the use of the beam model.