Objectives  Resonance Changer (RC) is an effective vibration damping device, which receives much attention in the field of longitudinal vibration control of marine shafting. As the RC's damping effect is closely related to the internal structural parameters,

  Methods  an analytical formula of sound pressure propagation in RC was derived based on the wave theory, and the physical relationship between the internal structural parameters and its vibration mechanism was constructed for engineering design. Then, the influence of design parameters of RC's external pipes and cavity on system insertion losses and sound pressure level in broad band as well as the sensitivity were analyzed.

  Results  The results show that, RCs can control the resonance peak of the main system well at its natural frequency.

  Conclusions  Attention should be paid to the external pipe size of RCs when considering the feature line spectrum suppression, and to the external cavity size when considering the overall control of sound pressure level in broad band.