The Study Of Absorption Theory For Macromolecule Functional Material

Underwater anechoic coating which has the ability of sound absorption, sound insulation, damping is important stealth submarine equipment. One of the purpose of sound absorption is to minimize the acoustic reflection, to consume majority of sound energy by the anechoic coating, so it is of great importance to select the material of underwater acoustic muffler cover. We choose rubber material traditionally, to reach our goal by use of rubber cavity resonator and acoustic impedance of the transition structure. However, because of the limited thickness, the traditional muffler cover can only meet the requirements when the frequencies are high. The frequency of sonar is growing lower and lower in practice, various scientists start to focus on enhancing the absorption without increasing the thickness. This requires a new seek for necessary sound-absorbing material and new mechanism of sound absorption.Recent years, with polymeric piezoelectric material extensive applied in transducer areas, such as functional materials. Domestic and foreign scientists gradually began to examine the use of functional polymer materials to reduce the structure vibration and sound absorption. Piezoelectric material is gradually widely applied as a typical feature of polymer materials.In this dissertation, we firstly represent a more comprehensive introduction to the traditional sound-absorbing material and new functional polymer materials research, and we give the detailed unique advantages of new type of polymer functional materials in the acoustic structure. Secondly, we do some research on the mechanism of the piezoelectric materials damping loss and acoustic impedance matching, as well as the problem in application of external loss circuit in piezoelectric material. Finally, we select the PVDF piezoelectric and rubber with the 2-2 piezoelectric layered composite structure, to do some simulation studies focusing on the properties of sound absorption whether external circuit is on or off, and frame the notion of making piezoelectric layered composite structural experimental samples with PVDF external circuit on.