Author(s)

Massaï Hatoumva¹, Emmanuel Siryabe^2*, Pierre Marechal³, Guy Edgar Ntamack⁴, Gambo Betchewe¹

¹Faculté des Sciences, Département de Physique, Université de Maroua, Maroua, Cameroon.
²Safran Helicopter Engines, Groupe Evaluation Non Destructive, Bordes, France.
³Laboratoire Ondes et Milieux Complexes (LOMC), UMR 6294 CNRS, Université du Havre, Le Havre, France.
⁴Groupe de Mécanique, Matériaux et Acoustique, P.B: 454, Département de Physique, Faculté des Sciences, Université de Ngaoundéré, Ngaoundéré, Cameroon.

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.

Reflection Coefficients, Transmission Coefficients, Defects, Multilayer, Peri-odic Structure

Hatoumva, M. , Siryabe, E. , Marechal, P. , Ntamack, G. and Betchewe, G. (2021) On the Simulation of the Influence of Defects on Immersed Plane Periodic Multilayer Viscoelastic Media. Open Journal of Acoustics, 11, 17-30. doi: 10.4236/oja.2021.112002.