Random vibration characteristics of marine rotating machinery systems under heave motion
As the heart of ships,the safe and stable operation of power machinery has a great impact on navigation safety.The implicated motion during navigation can have a significant impact on the vibra-tion of marine rotating machinery systems.Therefore,studying the dynamic characteristics and vibration control of marine rotating machinery under heave motion is of great significance.This paper mainly dis-cussed the nonlinear random vibration characteristics of a marine rotating machinery coupled airbag floating raft system under the combined action of heave motion and noise excitation.The airbag was modeled as a cubic nonlinear spring and a linear damper,and two linear springs and a linear damper were used to connect the rotating machinery and the floating raft.Then,Gaussian White Noise was in-troduced as a random excitation,and a stochastic dynamic model of the system under heave motion was established.Finally,the random vibration characteristics of the system were analyzed using numerical a-nalysis methods and compared with the simulation results of deterministic systems.The results show that:When the rotor speed is low,the amplitude difference between the random system and the deter-ministic system is small,but as the speed increases,the difference in vibration amplitude between the two increases;When the rotor is at high speed,the mass ratio of rotating machinery to floating raft has a greater impact on the amplitude of the system;In addition,the impact of noise excitation on the dynam-ic characteristics of stochastic systems also increases with the increase of rotor speed.The research re-sults provide theoretical basis and analysis methods for the random vibration design and dynamic analy-sis of ship rotating mechanical systems in heave motion.
heave motionharine rotating machineryairbagGaussian White Noiserandom vibration
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