Structural Topology Optimization Design Of Acoustic Functional Material

The structure of acoustic materials is an important factor affecting acoustic properties.In this paper,a topological optimization method based on genetic algorithm is established to complete the inverse structural design of acoustic models.The method demonstrates strong global search capability and applicability in designing broadband acoustic characteristic structures.The method provides a new design idea for the optimal design of acoustically functional materials and other research directions.Based on the method,the following models are established,analyzed and discussed in this paper:1.A topology optimization model for porous composites is established.The model is used to optimize the scatterer distribution inside a 5 cm thickness melamine sponge,and the average absorption coefficient of the optimized composite porous material exceed 0.8 in the range of 200～1600 Hz.The effects of different structures,different locations,different material parameters,different incidence angles and simplified structures on the absorption coefficient are investigated.2.A topology optimization model of the underwater acoustic cover is developed.Using this model to optimize the cavity topological characteristics inside the base material of the overlay and the dimensions of the embedded steel scatterer,the optimization results from 1 to10 k Hz have a high broadband sound absorption of 0.94.The absorption mechanism of this optimized result is analyzed,and the effects of different local structures,different incident conditions,different pressure conditions,and different material parameters on the absorption coefficient under this optimized structure are analyzed separately,and the key features are extracted for the comparison analysis of the simplified structure.3.A topological optimization model of broadband acoustic metasurface is established.Nine metasurface cells with a total phase gradient of 2 π at 3500 Hz were designed.Simulations and experiments are conducted to verify the anomalous reflection phenomenon,wave focusing and self-bending functions of the metasurface in the reflected acoustic field.Subsequently,a broadband acoustic metasurface with linear phase dispersion in the range of2000 to 5000 Hz is designed to achieve the same anomalous reflection angle and the same acoustic focusing phenomena under broadband incident sound conditions.The ability of the algorithm to modulate the phase dispersion and the potential mechanism to generate different phase differences are further investigated.