Limits on the use of electromagnetic shunt damper in control sound transmission through double-plate structures

It is well-known that the electromagnetic shunt dampers (EMSD) have been widely used in vibration control applications for simple beam and plate structures. In this study, the EMSD connected between incident and radiating plate is used to control the sound transmission through a double-plate structure at low frequency ranges. The EMSD consists of a coil, a permanent magnet, and a specially designed shunt circuit. First, a full structural-acoustic coupling modal model is developed to analyze the vibration and acoustical behaviour of the double-plate structures with EMSD system. Then different EMSD shunt circuit configurations are investigated. The sound transmission control performance of the EMSD is discussed based on different arameters of the shunt circuits. Finally, the experiment was performed. The numerical and experimental results show that the EMSD cannot control the in-phase modes of the double-plate structure. It means that the EMSD cannot be directly extended to control the sound transmission through the dou le-plate structures, which may limit on the use of EMSD in structural acoustic control applications.