STUDY OF WARPING TORSION OF THIN-WALLED-BEAMS WITH CLOSED CROSS-SECTION USING MACRO-ELEMENTS

A new method for computing the deformation of thin-walled beams with c losed cross-section under warping torsional loading is presented. In c omparison to the classical theory (Umanski), the hypothesis of no defo rmation of the contour of the cross-section of the beam is maintained and the assumption of no distortion of the cross-section plane is modi fied. The new approach gives better results than the classical theory when both are compared to a standard finite element technique (using s hell elements). The central idea of the new approach lies in the usage of a new finite element called a macro-element, which is especially w ell suited for thin-walled beam computations.