TY JOUR TI MODAL VIBRATION DIAGNOSTICS OF LATHES DESIGNS KW modal vibration diagnostics KW lathe KW spindle unit KW dynamic rigidity KW own frequency KW coefficient of modal damping KW modal ductility JO Bulletin of Bryansk state technical university AU Brengauz , A.. AU Molchanov , A.. AU Dosko , S.. AU Bykov , P.. PY 2016 IS 2016 PB Bryansk State Technical University