Vibrations control in cruise ships using magnetostrictive actuators

Abstract

A big problem in cruise ships is related to noise and vibrations generated by engines and exhaust stacks. Reduction or control of ship noise has traditionally been implemented by passive means, such as by the use of vibration isolation mounts, flexible pipe-work, and interior acoustic absorbing materials. However, these passive noise control techniques are effective mostly for attenuating high-frequency noise, while they are generally ineffective for controlling the low-frequency one. This paper presents an active vibration control of ship bulkheads based on independent modal control technique using magnetostrictive actuators. In the first part of the research, a mock up of the vibrating bulkhead is reproduced in laboratory and a mechanical model of both the system and actuators has been realized. The modal control has then been simulated focusing on actuators and sensors position and number to improve the system's controllability and observability properties and hence allow to obtain optimal performances in terms of vibration reduction. The influence of boundary conditions has also been taken into account in order to be able to predict the control logic performances in the various possible scenarios. ©2010 Society for Experimental Mechanics Inc.