TY JOUR TI RATIONAL SECTIONS OF THE BEAM AT THE SKEW BENDING KW skew bending KW rational section of a beam KW extremal stress KW isoperimetric task JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Yur'ev, A.G. AU Tolbatov, A.A. AU Smolyago, N.A. AU Yakovlev, O.A. PY 2017 IS 2 PB Belgorod State Technological University named after V.G. Shukhov