Study on vibration isolation performance of elastic coupling under longitudinal excitation

According to longitudinal vibration differential equations of ship propulsion shafting, deduced transfer matrix of propeller, uniform shaft segment and thrust bearing which composed propulsion shafting. Given longitudinal vibration natural frequency of propulsion shafting using the transfer matrix solver, and compared with finite element simulation results to verify the accuracy of the finite element model. Then analysis the effect of elastic coupling axial stiffness on modal frequencies of shafting longitudinal vibration and vibration isolation performance through simulation. Results show that: elastic coupling can effectively isolate the propulsion shafting vibration transmitted to the propulsion motor; when the axial stiffness ratio of thrust bearing and elastic coupling is greater than 50, the impact of elastic coupling axial stiffness on longitudinal vibration natural frequency of propulsion shafting and acceleration level and axial displacement of thrust bearing is very small; when the stiffness ratio is greater than 100, the elastic coupling can achieve better vibration isolation effect.