A proposal of a new model of macro element used to analyse the ship hull torsion - closed section - as thin walled beam using macro elements is treated. The outline of the section is considered as polygonal one. The material is considered as an orthotropic one. For a straight line portion of cross section outline is corresponding a longitudinal strip plate. Due to the warping torsion of the thin walled beam, in the strip plate the stretching-compression, bending and shearing occur. The stiffness matrix of the macro-element is obtained by assembling the stiffness matrices of the strips.In the local strength analysis of the ship hull, the local loading is supposed to be known. These loadings occur from the global strength of the ship hull. An important loading of the ship hull is torsion treated as thin walled beam (frequently as closed section).
