Periodic Acoustic Structure Design Based on the Second-Order Butterworth Acoustic Filter

The paper proposes a design method of periodic acoustic structures composed filters. Based on acoustic-electric analogy, the second-order Butterworth filter is first designed, which comprises main pipe, Helmholtz resonator, short tube and an expansion cavity. Second, are constructed by taking as original unit cell or modifying to obtain modified cell, periodically arraying cells along axial direction pipe. Then, influences circumferential arrangements filtering performances investigated, respectively. Next, multi-period structure models established their transmission losses simulated compared. Finally, low-frequency broadband constructed. research shows that, period has no influence resonance frequency structure, but contributes ranges; increase in can result shift towards high frequencies great increment bandwidth; combining with different significantly widen range; be implemented increasing periods structures.