transformation matrix

Hi all,

My question is about this transformation matrix T for beam elements using 3 or more nodes (quadratic or higher formulation).

When
programming beam elements in 2D or 3D one usually formulates the shape
functions etc. in ‘local’ beam coordinates (e.g. x’). So the beam stiffness matrix
will be formulated using this local coordinate system. For assembly of the ‘global’
system one transforms this local matrix to global coordinates using a
transformation matrix T.