Experiments on vibration transmission control in a shaft-hull system excited by propeller forces via an activemulti-strut assembly

Abstract

The active control of lateral vibration transmission in a shaft-hull system with an active multi-strut assembly was investigated experimentally. The lateral vibration of the shafting system excited by the propeller forces transmits to the hull structure through the active multi-strut assembly, and the embedded actuator in each strut generates control forces to suppress vibration transmission. Modal testing was conducted and the characteristics of the hull structure were obtained. The excitation was exerted by two shakers mounted on the stern bearing housing. The performance of vibration suppression was verified for two control strategies that use three and six error transducers, respectively. Experimental results have demonstrated that the active multi-strut assembly in combination with the adaptive control method is able to suppress the vibration transmission from the shaft to the hull, and accordingly reduces the vibration of the hull surface. Moreover, the control strategy using six error transducers is of stronger cross coupling in the control channels as compared to that using three error transducers, which consequently makes it harder to implement active control.