On synchrophasing control of vibration and sound radiation for a floating raft vibration isolation system

For the purpose of solving the problems of vibration transmission and sound radiations in ships,synchrophasing control technology was presented. The phases of multiple rotating or reciprocating machines installed on a floating raft were adjusted by synchrophasing control to minimize vibration transmission from the floating raft to a hull structure,and then as a result the sound radiation from the hull structure was reduced reasonably. Relative phases between each of the two vibrating machines were optimized in order to minimize the sum of the squared acceleration responses of the hull structure by using genetic algorithm. Synchrophasing control for the floating raft vibration isolation system installed on a flexible hull-like structure was investigated theoretically and experimentally. The results show that by comparing the optimal phases and the least optimal phases,the maximum reduction of the sum of squared acceleration responses measured by 22 error sensors on the hull structure and the maximum reduction of the mean squared sound pressures measured by 10 microphones around it are up to 13. 2 dB and 20. 4 dB by synchrophasing control,respectively. Synchrophasing control is a simple and efficient method for controlling the vibration transmission and sound radiations of the hull structure.