Acoustic topology optimization of porous material distribution by FMBEM-based sensitivity analysis
* Presenting author
This work applies an acoustic topology optimization technique for structure surface design with porous materials, where the fast multipole boundary element method (FMBEM) is employed for sound scattering analysis. The acoustic absorption characteristics of porous materials are numerically modeled using the Delany-Bazley-Miki empirical model, and are subsequently introduced to impedance boundary conditions in boundary element (BE) simulations. Based on the solid isotropic material with penalization (SIMP) method, the optimization is performed by setting the artiﬁcial element densities of porous material as design variables and the minimization of sound pressure at reference points as design objective. In this study, a fast sensitivity analysis approach based on an adjoint variable method (AVM) and fast multipole method (FMM) is developed to calculate the sensitivities of the objective function with respect to a large number of design variables. We validate the proposed topology optimization approach through numerical examples of acoustic scattering over a single infinite cylinder and multiple cylinders. Remarkable pressure attenuations due to porous material are observed in the simulation results. Furthermore, we demonstrate the ability of the proposed approach to handle large scale problems.