The assessment of active vibration isolation performance of rotating machinery using power flow and vibrational energy: Experimental investigation

Abstract

The aim of vibration isolation for rotating machinery is to reduce the energy from the vibration source through transfer paths into the receiver structure. However, the direct measurement of energy characteristics that have been thoroughly researched in theory and numerical simulation is always difficult to implement. In this paper, power flow combined with vibrational energy is applied to assess the performance of active vibration isolation of rotating machinery. The indirect measurement methods associated with both power flow and vibrational energy are proposed and a link between them is established. As the first step in experimental investigation, a simple test rig is performed to verify the proposed measurement methods. The power flow into the foundation is calculated by the proposed time averaged, fundamental frequency and second harmonic frequency methods; the vibrational energy of the foundation is estimated by the driving impedance and mobility methods. The second step is to build another experimental rig for imitating the rotating machinery with active vibration isolation. Under multiple excitations, the power flow from the unbalanced rotor excitation through each actuator into the foundation is calculated by the proposed fundamental frequency method; the vibrational energy is calculated by the proposed mobility matrix method. Finally, comparison of assessing the performance of active vibration isolation between using acceleration and force and using the two energy characteristics are carried out.