Jintao Liu¹, Juan Zhao¹, Xiaowei Shen^1,2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.2, pp. 981-1003, 2023, DOI:10.32604/cmes.2022.021641

Abstract In this work, an acoustic topology optimization method for structural surface design covered by porous materials is proposed. The analysis of acoustic problems is performed using the isogeometric boundary element method. Taking the element density of porous materials as the design variable, the volume of porous materials as the constraint, and the minimum sound pressure or maximum scattered sound power as the design goal, the topology optimization is carried out by solid isotropic material with penalization (SIMP) method. To get a limpid 0–1 distribution, a smoothing Heaviside-like function is proposed. To obtain the gradient value More >

Jie Wang, Fuhang Jiang, Wenchang Zhao, Haibo Chen^*

CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.2, pp. 645-681, 2021, DOI:10.32604/cmes.2021.015894

Abstract A combined shape and topology optimization algorithm based on isogeometric boundary element method for 3D acoustics is developed in this study. The key treatment involves using adjoint variable method in shape sensitivity analysis with respect to non-uniform rational basis splines control points, and in topology sensitivity analysis with respect to the artificial densities of sound absorption material. OpenMP tool in Fortran code is adopted to improve the efficiency of analysis. To consider the features and efficiencies of the two types of optimization methods, this study adopts a combined iteration scheme for the optimization process to More >

C.J. Zheng¹, H.B. Chen¹, T. Matsumoto², T. Takahashi²

CMES-Computer Modeling in Engineering & Sciences, Vol.79, No.1, pp. 1-30, 2011, DOI:10.3970/cmes.2011.079.001

Abstract A fast multipole boundary element approach to the shape sensitivity analysis of three dimensional acoustic wave problems is developed in this study based on the adjoint variable method. The concept of material derivative is employed in the derivation. The Burton-Miller formula which is a linear combination of the conventional and normal derivative boundary integral equations is adopted to cope with the non-uniqueness problem when solving exterior acoustic wave problems. Constant elements are used to discretize the boundary surface so that the strongly- and hyper-singular boundary integrals contained in the formulations can be evaluated explicitly and More >