Abstract
This work deals with the study of a plane periodic multilayer structure in which the elementary stack consists of two plates in contact: one in aluminum (AL) and the other one in polyethylene (PE). These isotropic materials, present a high acoustic impedance contrast. The attenuation of the longitudinal and transverse waves is taken into account in the polyethylene but neglected in the aluminum plate. The effect of different defects is analyzed. Firstly, we focus on the effect of the presence of grease inclusion in the polyethylene plate (considering the two plates of the elementary stack in perfect contact). Secondly, the effect of disbond simulated by the insertion of a thin Teflon layer between the interfaces of the two layers constituting the elementary stack of the multilayer structure is investigated. Finally, the effect of the stacking sequences of the multilayer is analyzed. In order to obtain the effective acoustic parameters of polyethylene layer, allowing to evaluate the reflection and transmission coefficients using the stiffness matrix method developed by Rokhlin et al., four homogenization models are analyzed, then the best one to our configuration is chosen. The comparison of the simulation results is carried out.
Highlights
Periodic multi-layered media are widely studied because of their very interesting properties such as exhibiting absolute or local band gaps in their dispersion curves
This work deals with the study of a plane periodic multilayer structure in which the elementary stack consists of two plates in contact: one in aluminum (AL) and the other one in polyethylene (PE)
The multilayer structure is immerged in a coupling medium
Summary
Periodic multi-layered media are widely studied because of their very interesting properties such as exhibiting absolute or local band gaps in their dispersion curves. Our theoretical approach is based on the stiffness matrix [3] method which ensures unconditional numerical stability, whatever the frequency range and the incidence angle This method allows to study the forbidden and passbands from the calculation of the reflection and transmission coefficients. Maréchal et al [7] showed that the number of periods necessary to obtain stable forbidden and passbands depends on the geometrical and physical characteristics of the viscoelastic plate. For their configurations studied, they demonstrated that three periods (N = 3) ensure the convergence of the reflection spectrum (or transmission spectrum). Khaled et al [10] investigated the influence of the insertion
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
