The damping structure of polymer materials is mainly divided into free damping layer and constrained damping layer. The free damping layer is to paste or spray the vibration absorbing material directly on the vibration damping parts. In this way, the damping value and modulus of the material are required to be high and wide. The constrained damping layer is to clamp the vibration absorbing material between the metal sheet or composite material with a certain rigidity and the parts to be damped, so as to improve its vibration absorbing performance.
Generally, nitrile rubber, polysulfide rubber, butyl rubber, polyurethane elastomer, polyvinyl butyral, methyl polyacrylate, plasticized PVC, IPN polyisobutyl ether, EPDM and EPDM of semi IPN and various foamed plastics can be selected as vibration absorption and noise reduction materials. These damping materials are widely used in rocket, missile, satellite, precision instrument, bridge support, high-rise building seismic structure and so on.