Analysis Of The Acoustic Concealing From The Underwater Polymer Matrix Piezoelectric Composites

Underwater acoustic concealing technology has always been the most valuable research field for Security Department of the Navy over the world. There are mainly two types of acoustic concealing technologies. One type is the passive approach ,which uses the viscoelastic material cover (anechoic tile) to suppress the acoustic reflection, and the other type is called active control approach,which means imposing an appropriate control voltage on the piezoelectric material layer. Coupling with the property of the material,it can be very effective to reduce the acoustic reflection. Two methods have their own characteristics and limitations. A new polymer matrix piezoelectric composite material,which has both the properties of the piezoelectric and viscoelastic materials comes out currently . The feasibility of underwater acoustic reduction with this new type of material is theoretically discussed in this thesis.In this thesis, the constitutive relations and material parameters of the polymer matrix piezoelectric composite material have been studied .On the basis of the Thomson-Haskell matrix method,we have derived the reflected transform matrix of the bi-laminated plates using the new material and calculated a semi-analytical solution to the problem by using matlab. Additionally, the reflection law has been systematically studied under the different conditions,concluding a variety of material parameters, the control voltage, geometric parameters, incident angle and frequency and so on. The studies have showed that: the polymer matrix piezoelectric composite material takes the advantages of both the viscoelastic material and the piezoelectric material and the use of the new material has a superior nature than the traditional materials to the suppression of underwater acoustic reflection.