Sound absorption performance of various nickel foam-base multi-layer structures in range of low frequency

Preparation and Characterization of Gradient Compressed Porous Metal for High-Efficiency and Thin-Thickness Acoustic Absorber

“…The gradient-structural porous metal and the multilayer porous metal have been developed to further improve absorption efficiency and reduce total thickness [11,12,13,14,15]. Zhu et al [11] had prepared metal fiber porous material with gradient pore structures, and average sound absorption coefficient in the 50–6400 Hz for the optimal sample with thin-thickness of 3.0 mm reached 35%.…”

“…Chen et al [13] had fabricated the multilayer porous fibrous metal for the sound absorption, and the average sound absorption coefficient in the 500–5000 Hz range reached 93.4% for the optimal four-layer porous fibrous metal with thickness of 50 mm. Cheng et al [14] had developed the various nickel foam-based multilayer sound absorbing structure, and the optimal sound absorption coefficient could reach 0.4 in 1000–1600 Hz range for the composite structure of five-layer foam with backed 5-mm-thick cavity. The porous metal fiber materials with gradient structure was fabricated by Wang et al [15], and its average absorption coefficient reached 37.52% in the 50–6400 Hz range when thickness of the three-layer gradient structure was 6 mm.…”

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

“…Although many sound absorbers made of wood or cork have been developed and can exhibit fine sound absorption performance, they will be favorable to use in the workshops when their fire resistance, mechanical strength, and maintainability are improved in future, because the materials used in the workshops should obey the stricter requirements. Among the present common sound absorbing materials, porous metal is considered as one potential candidate to fabricate the sound absorber for mass production and large-scale application in workshops, and many sound absorbers that consist of porous metal have been developed [8][9][10][11][12][13][14]. Ru et al [8] prepared the porous copper by the resin curing and foaming method, which exhibited a greater sound absorption capacity than the lotus-type copper.…”

“…Chen et al [12] presented a method for calculating and optimizing the sound absorption coefficient of the multi-layered porous fibrous metals in the low frequency range, and the numerical examples demonstrated that the optimization model was very applicable and efficient. The various nickel foam-based multilayer sound absorbing structures were developed by Cheng et al [13], which could achieve the optimal sound absorption coefficient of 0.4 in the 1000-1600 Hz for the composite structure of five-layer foams with a backed 5 mm-thick cavum. Ao et al [14] conducted the sound absorption characteristics and the structure optimization of porous stainless steel fibrous felt materials, and it indicated that the sample with excellent sound absorption performance could be prepared by adjusting the match between the mean pore size and the fibrous diameter for different frequencies.…”

“…Ao et al [14] conducted the sound absorption characteristics and the structure optimization of porous stainless steel fibrous felt materials, and it indicated that the sample with excellent sound absorption performance could be prepared by adjusting the match between the mean pore size and the fibrous diameter for different frequencies. This research [8][9][10][11][12][13][14] proved that sound absorption behavior of the porous metal was determined by its structural parameters, and it could be improved by using some optimization methods, which indicated that the suitable optimization was a crucial procedure to develop a novel sound absorber made of the porous metal.…”