flexural-torsional vibrations of thin-walled beam, as the a system of connected plates, spatial construction, plate properties.

Finite element method in «MSC Nastran» study the dynamic characteristics of the hot-rolled thin-walled steel I-beam. A mathematical model that considers the rod as the spatial construction made of a of articulated plates are offer. The obtained numerical results are compared with the known theoretical solution V.Z. Vlasov and decisions considering shear deformation in the middle plane. It is found that the transition to the spatial design of the rod, in some cases, accompanied by the appearance of new frequencies. Increasing numbers I-beam profile leads to thicken the frequency spectrum. Identified effects are not reflected in the theory of thin-walled beam.

Seregin, Sergei Valerevich Senior lecturer in "Building and Architecture", Komsomolsk-on-Amur State Technical University, Komsomolsk-on-Amur