An experimental investigation into the semi-active and active control of longitudinal vibrations in a large tie-rod structure

An experimental study into the use of one semi-active and two active control devices employed to attenuate the transmission of longitudinal vibrations on a large tie-rod structure is described. A tie-rod structure similar to that found in marine machinery installations was assembled in the laboratory. This type of structure was chosen because it is difficult to apply standard passive techniques due to the static stiffness requirement. A tunable pneumatic vibration absorber was used as the semi-active device, and an inertial electrodynamic exciter and a magnetostrictive actuator were used as the active devices. The way in which these devices couple into and modify the dynamic behaviour of the tie-rod structure is discussed, and experimental results are presented showing the effectiveness of the control measures in attenuating longitudinal vibrations. Significant reductions in transmitted vibrations were achieved by all the devices and the merits of each method are discussed.