optimum design of a viscoelastic vibration absorber for counter-rotating systems

The small distance between two rotating shafts can disturb them, cause interference in their performance, and affect the system’s efficiency. the application of the counter-rotating double shafts has some specific benefits. for example, these shafts can be used under the water to neutralize the driving torque effect, prevent the submarine’s self-propulsion, and increase the submarine’s power to move forward and maneuver. the aim of this study is designing an optimum viscoelastic vibration absorber for a counter-rotating double shaft to deal with the vibration. in order to overcome vibrations, viscoelastic cylinders are modeled as distributed spring and damper which are considered between the two shafts, and their vibration equations are obtained. optimal position and distributed stiffness and damping coefficients are determined using a particle swarm optimization algorithm. the objective function to be minimized is defined as the relative distance between shafts which is controlled by equivalent stiffness and damping coefficients of considered viscoelastic vibration absorber. the present results show that applied viscoelastic polymer with the nearest features to the optimum values can drastically decrease the relative distance between shafts and absorb the vibration of rotating shafts.