Speaker
Description
Acoustic topology optimization is a broad topic, with one sub-group being structural optimization. In this discipline, we aim to distribute soundhard material to achieve specific acoustic properties, primarily through a density-based approach. One typical example is the transition zone between two waveguides, soundhard structures that restrict wave propagation and often enforce a unidirectional field.In this work, we assume that the cross-sections of both waveguides are equal while designing our soundhard structures to achieve a given broadband transmission frequency response. Using lowpass, highpass, bandpass, and bandstop target functions, we synthesize one design for each transmission profile. To avoid modelling thermoviscous losses and ensure manufacturability with standard 3D printing methods, we use a robust filter approach that combines erode, center and dilate filters in a min/max optimization problem.The obtained designs mostly matched the target response within the specified range. The inherent property of structural filters to always transmit low-frequency waves made it hard for the optimizer to converge for highpass and bandpass designs. Lowpass and bandstop filters performed very well, even below the optimization's frequency range. The initial studies showed promising results, motivating future research and parameter studies to further solidify the understanding of the filter devices' working principles.