First investigations on subtractive modeling with the condensed transfer functions method
Résumé
Acoustic coatings are of primary importance when investigating vibro-acoustic behavior of submerged cylindrical shells. These coatings can be applied on the entire circumference of the shell, or only on a certain stretch or a given angular domain. The latter configuration induces in the models a coupling of the shell circumferential orders, thus resulting in much heavier computation costs. To tackle this issue, it is suggested to simulate the vibroacoustic behavior of the partially coated submerged shell by using subtractive modeling. The principle of the method is to model the partially coated submerged shell, from the model of the fully coated submerged shell to which we remove a given part of the coating. In order to test its validity and its robustness to model errors, the method was at first applied to the academic case of the decoupling of Euler-Bernoulli beams. Several beam models were considered for the subtraction (analytical, FEM 1D, FEM 3D). The numerical results were compared to analytical calculations. Through this study, the method?s sensibility to model errors was investigated and the results allow to giving first validation of the method. Hence, the principle of subtractive modeling is, in a second time, extended to a three-dimensional system through the study of the scattering of a plane wave by a rigid sphere.
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