Bending Vibration Analysis of Composite Transmission Shaft

To improve the dynamic characteristics of a helicopter transmission shaft,bending vibration of a composite transmission shaft was investigated under a non-inertial system.Based on theorem of the motion for center of mass,a bending vibration equation for a tilting fiber composite transmission shaft with two supports was derived under a non-inertial system,and its solution was obtained by the Galerkin method.The effects of eccentric mass,damping,inertia force and gravity on the vibration amplitude were analyzed.The results show that a fiber composite transmission shaft has a larger bending natural frequency than a steel or aluminum alloy transmission shaft and a larger frequency range of non-resonance between adjacent orders,smaller static deflection and amplitude.When inertia force of a transmission shaft does not change,its maximum transversal displacement is equal to the sum of the static deflection produced by inertia force and gravity and the amplitude of deflection induced by eccentric mass,and when inertia force of a transmission shaft changes,dynamic deflection is produced.