Acoustic scattering by laminated plates with viscoelastic layers

The effect of addition of viscoelastic layers on the acoustic scattering quadrupoles near the trailing edge of composite plates is evaluated. For modelling of the viscoelastic material the complex modulus approach was used in combination with the frequency-temperature correspondence principle. The computation of laminate stiffness is based on Classical Lamination Theory. We employ a numerical method to compute the acoustic field scattered by finite elastic plates. Based on a Boundary Element Method, this procedure solves the Helmholtz equation subject to boundary conditions related to the vibration of the plate. These conditions are recast in terms of the vibration modes of a rectangular plate. Results show that by adding viscoelastic plies to a composite plate we modify the far-field sound scattered by turbulence near an edge of the plate. Parametric studies show that this approach reduces scattered noise at resonance frequencies. Discussions on the operating temperature, positioning and thickness of the viscoelastic layers are providedCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES301053/2016-2; 305277/2015-4; 310523/2017-688882.180835/2018-0125th AIAA/CEAS aeroacoustics conference2019Delft, HolandaThis study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) -Finance Code 001. Maurício M. Nilton thanks the financial support received for this work from CAPES/PROEX Grant No. 88882.180835/2018-01. André V. G. Cavalieri thanks the financial support received for this work from the national research council CNPq, Grant No. 310523/2017-6. Maurício V. Donadon thanks the financial support received for this work from the national research council CNPq, Grant No. 301053/2016-2. William R. Wolf thanks the financial support received for this work from the national research council CNPq, Grant No. 305277/2015-