Coupled Vibration of Lateral and Torsional Vibrations in a Rotating Shaft Driven through a Universal Joint - Derivation of Equations of Motion and Stability Analysis -

유니버셜 조인트에 의해 구동되는 회전축의 횡진동과 비틀림진동의 연성진동 - 운동방정식의 유도 및 안정성해석 -

This paper presents theoretical analyses for unstable vibrations caused by the couple of bending and torsion in a rotating shaft driven through a universal joint. A driving shaft is assumed to be rigid and to rotate with a constant angular velocity. The driven shaft system consists of a flexible shaft with a circular section and a symmetrical rotor attached at a point between the shaft ends. Equations of motion derived hold with an accuracy of the second order of shaft deformations, and are analyzed by the asymptotic method. The vibrations become unstable when the driving shaft rotates with the angular velocity to be approximately equal to half of the sum of the natural frequencies for whirling and torsional vibrations.