Torsional buckling of thin-walled beams in presence of bimoment induced by axial loads

In this paper the influence of the bimoment induced by external axial loads on the elastic torsional buckling of thin-walled beams with open cross-section is studied. The governing differential equations of a deformed thin-walled beam consistent with Vlasov's classical assumptions are derived applying the principle of virtual displacements. It is shown that in the cross sections with lack of symmetry the bimoment can considerably affect the torsional buckling load. The obtained results are verified using ANSYS finite element software.Original Abstract: U clanku je proucen utjecaj bimomenta na stabilnost tankostjenog stapa s otvorenim poprecnim presjekom uslijed vanjskog aksijalnog opterecenja. Primjenom principa virtualnih pomjeranja izvedene su diferencijalne jednadzbe deformiranog tankostjenog elementa u skladu s klasicnim pretpostavkama Vlasova. Pokazano je da kod poprecnih presjeka koji nemaju os simetrije bimomenat moze znacajno utjecati na u vojnu kriticnu silu. Dobiveni rezultati su provjereni primjenom programa ANSYS.