3D Printing of Polymeric Multi-Layer Micro-Perforated Panels for Tunable Wideband Sound Absorption

Abstract

The increasing concern about noise pollution has accelerated the development of acoustic absorption and damping devices. However, conventional subtractive manufacturing can only fabricate absorption devices with simple geometric shapes that are unable to achieve high absorption coefficients in wide frequency ranges. In this paper, novel multi-layer micro-perforated panels (MPPs) with tunable wideband absorption are designed and fabricated by 3D printing or additive manufacturing. Selective laser sintering (SLS), which is an advanced powder-based 3D printing technique, is newly introduced for MPP manufacturing with polyamide 12 as the feedstock. The acoustic performances of the MPPs are investigated by theoretical, numerical, and experimental methods. The results reveal that the absorption frequency bandwidths of the structures are wider than those of conventional single-layer MPPs, while the absorption coefficients remain comparable or even higher. The frequency ranges can be tuned by varying the air gap distances and the inter-layer distances. Furthermore, an optimization method is introduced for structural designs of MPPs with the most effective sound absorption performances in the target frequency ranges. This study reveals the potential of 3D printing to fabricate acoustic devices with effective tunable sound absorption behaviors and provides an optimization method for future structural design of the wideband sound absorption devices.

Keywords: 3D printing; acoustic absorption; micro-perforated panel; multi-layer structure; selective laser sintering.

Figure 1

The schematic diagram of an MPP, which consists of a thin panel, an air gap, and a rigid wall.

Figure 2

The schematic demonstration of the single-layer, double-layer, and triple-layer MPPs.

Figure 3

3D printed samples of MPPs and the setup of the acoustic absorption test.

Figure 4

The schematic demonstration of the multi-layer MPPs: (a) a double-layer MPP and (b) a triple-layer MPP in the impedance tube.

Figure 5

Comparison of the absorption coefficients of the single-layer, double-layer, and triple-layer MPPs obtained by the theoretical predictions, numerical simulations, and experiments.

Figure 6

The microscope images of a printed panel: (a) two perforations in imperfect circular shapes and (b) a part of the unsmooth rim with grains.

Figure 7

Comparison of absorption coefficients of MPPs with varying air gap distances obtained by the theoretical predictions, numerical simulations, and experiments.

Figure 8

Comparison of absorption coefficients of the MPPs with varying inter-layer distances obtained by the theoretical predictions, numerical simulations, and experiments.

Figure 9

The frequency coverages of the single-layer and double-layer MPPs at each L varying from 10 mm to 200 mm.

Figure 10

The frequency coverage of the triple-layer MPPs at L = 190 mm.

Figure 11

The maximum frequency coverage of single-layer, double-layer, and triple-layer MPPs at a different L.

Figure 12

Absorption coefficients of optimized MPPs obtained by theoretical predictions, numerical simulations, and experiments: (top) double-layer MPP and (bottom) triple-layer MPP.