Optimization and Validation of Sound Absorption Performance of 10-Layer Gradient Compressed Porous Metal

Abstract

Sound absorption performance of a porous metal can be improved by compression and optimal permutation, which is favorable to promote its application in noise reduction. The 10-layer gradient compressed porous metal was proposed to obtain optimal sound absorption performance. A theoretical model of the sound absorption coefficient of the multilayer gradient compressed porous metal was constructed according to the Johnson-Champoux-Allard model. Optimal parameters for the best sound absorption performance of the 10-layer gradient compressed porous metal were achieved by a cuckoo search algorithm with the varied constraint conditions. Preliminary verification of the optimal sound absorber was conducted by the finite element simulation, and further experimental validation was obtained through the standing wave tube measurement. Consistencies among the theoretical data, the simulation data, and the experimental data proved accuracies of the theoretical sound absorption model, the cuckoo search optimization algorithm, and the finite element simulation method. For the investigated frequency ranges of 100–1000 Hz, 100–2000 Hz, 100–4000 Hz, and 100–6000 Hz, actual average sound absorption coefficients of optimal 10-layer gradient compressed porous metal were 0.3325, 0.5412, 0.7461, and 0.7617, respectively, which exhibited the larger sound absorption coefficients relative to those of the original porous metals and uniform 10-layer compressed porous metal with the same thickness of 20 mm.

Improving and Optimizing Sound Absorption Performance of Polyurethane Foam by Prepositive Microperforated Polymethyl Methacrylate Panel

“…Based on the theoretical sound absorption model of the polyurethane foam in Section 2.1.1 and the experimental data obtained in the following measurement, identification of acoustic characteristic parameters of the polyurethane foam was achieved by the cuckoo search algorithm [24][25][26][27], and the calculation flow chart is shown in Figure 2. In this study, experimental data of sound absorption coefficients of the polyurethane foam with thicknesses of 20 mm, 30 mm, 40 mm, and 50 mm were measured and utilized in this identification process, and the detected frequency points were in the range of 100-6000 Hz with the interval of 100 Hz, which indicated that there were 240 groups of data (4 × 60 = 240).…”

“…Similar with the polyurethane foam, porous metal was another common porous material used in the field of sound absorption [8,17,22,27,29,33,35]. Besides common standard porous metal, some novel sound absorbers had been proposed, such as uniform compressed porous metal [35], gradient compressed porous metal [8,22,27], microperforated compressed porous metal panel [29], and so on. The horizontal comparisons of the actual average sound absorption coefficient of the optimal composite sound absorbing structure with that of other porous materials were conducted when total thickness was 20 mm, as shown in Table 5.…”

“…Proposed optimal composite structure 0.5296 0.6482 Utilized original polyurethane foam 0.1885 0.3392 Standard porous metal [27] 0.1529 0.2477 Uniform compressed porous metal [27] 0.2098 0.4531 Gradient compressed porous metal [27] 0.3325 0.5412 Microperforated compressed porous metal panel [29] 0.1657 0.3403…”

“…The sound absorption mechanism of the polyurethane foam and that of the composite sound absorbing structure were investigated according to their structures, and their theoretical sound absorption models were constructed based on the Johnson-Champoux-Allard model [15][16][17] and Maa's theory [18][19][20] by the transfer matrix method [21][22][23]. Afterwards, identification of acoustic characteristic parameters of the polyurethane foam and optimization of structural parameter of the composite structure were realized through the cuckoo search algorithm [24][25][26][27]. Later, the composite structure was verified by the finite element simulation method [28][29][30][31] and validated through the standing wave tube measurement [32][33][34][35].…”

Identification of Acoustic Characteristic Parameters and Improvement of Sound Absorption Performance for Porous Metal

“…Normally, no matter for the common porous metal or for composite sound-absorbing structure, the structural parameters must be optimized to achieve the satisfactory sound absorption performance under certain constraint conditions [16][17][18][19][20][21]. Acoustic topology optimization of porous material distribution based on the adjoint variable fast multipole boundary element method was conducted by Zhao et al [16], and its ability to handle the large-scale problems was validated through numerical examples of acoustic scattering over a single cylinder and multiple cylinders.…”