TY JOUR TI VIBRATORY ACTIVITY INVESTIGATION OF GRINDING MACHINE ELECTRIC SPINDLES KW bearings KW vibratory acceleration KW preload KW spectral properties KW frequency KW rotor JO Bulletin of Bryansk state technical university AU Gasparov, E.S. AU Gasparova, L.B. AU Markosyan, G.A. PY 2021 IS 2021 PB Bryansk State Technical University