For some reason, I am writing a finite element program using the Timoshenko beam element and Total Lagrangian Formulation for geometric nonlinear analysis.

But I fail to get correct results with my program. I am suspecting the problem may be caused by the use of non-vector rotational variables.

I don't know how to insert equations, so I enclose the file with the description of the problem.

Anyone can help would be greatly appreciated.