**Yang Yang 1,2,\*, Guang Pan 1, Shaoping Yin <sup>2</sup> and Ying Yuan <sup>3</sup>**


Received: 5 November 2019; Accepted: 31 December 2019; Published: 3 January 2020

**Abstract:** Vibration control is important in maintaining the silence of the underwater vehicle. Among the many methods of vibration control, isolation is by far the most efficient approach. However, as one of the major vibration sources in underwater vehicle, the vibration isolation of the sea-water pump has not been well explored. The sea-water pipe is the primary vibration transmit path from the sea-water pump to the housing. In order to realize the vibration isolation of the sea-water pump, the sea-water pipe must have certain flexibility and damping. In this study, scaled model tests were carried out to investigate the isolation effectiveness of flexible pipes in isolated sea-water pump. Specifically, three types of flexible pipes, i.e., double layer metal bellows (DLMB), rubber pipes (RP) and bellows coated rubber (BCR) were designed and tested. Tests were carried out under the operation rotate speeds of the sea-water pump. Our results show that compared with single layer metal bellows (SLMB), the isolation effectiveness of DLMB and BCR were significant and stable in high frequency regions. The optimal pipe can be chosen for different vibration reduction requirements in practical engineering.

**Keywords:** underwater vehicle; sea-water pump; vibration isolation; flexible pipes
