Authors: Ying Wu Wang, Xiao Qing Zuo, Xian Ning Chen
Abstract: Al-Si12 alloy foams were fabricated by filtration method, and the Al-Si12 alloy foam core mufflers were made by using the fabricated Al-Si12 alloy foams. The preparation and sound absorption property of Al-Si12 alloy foam core muffler has been studied. The results show that sound absorption property of Al-Si12 alloy foam core muffler increases with the decreasing of pore diameter and the widening of the pore diameter range of Al-Si12 alloy foam core. Being superior to conventional sound-absorbing materials core mufflers, Al-Si12 alloy foam core muffler especially fits in noise control in hot, wet, and open-air environments.
1687
Authors: Chu Wang Su, Quan Ping Yuan, Jing Da Huang, Kang Yang
Abstract: The composite acoustics board with pore-tank structure and variable cross section structure are made of Medium Density Fiberboard(MDF) as base material, Mytilaria laosensis sheet as veneer board, and sound absorption mat as the substructure material with the micro-perforation interlayer structure. The test was carried out to compare the absorption coefficient of Mytilaria laosensis sheet and nine samples by standing wave tube The test result shows that Mytilaria laosensis sheet has a low sound-absorbing performance itself, and its sound-absorption coefficient in all frequency ranges less than 0.3 and cannot be used as the sound-absorption board alone; The variable cross section structure sound-absorption board has a better performance than the pore-tank structure; When using the micro-perforation layer structure, the sound absorption board performs better and the sound absorption coefficient improves markedly in middle and low frequency scope.
95
Authors: Joyjeet Ghose, Vinay Sharma, Surender Kumar
Abstract: Experimental investigation of sound absorption characteristics of aluminium foam is carried out under laboratory test conditions. The studies revealed that the developed aluminium foam have excellent sound absorption properties and is comparable with other sound absorbing materials. Excellent sound absorption property coupled with good mechanical properties makes this material ideal for sound absorption under difficult situations. Experimental results revealed that the thickness of the specimen affects the sound absorption properties of the material, and there exists an optimal thickness, at which sound absorption coefficient is maximum. Experimental evidence showed that presence of damaged cell edges, open and/or semi-open cells in the specimen surface, enhances the sound absorption capability of the material.
1145
Authors: Xiao Hong Zhang, Jiang Tao Zhang
Abstract: According to two parameters combination of the material thickness and air-gap depth, from the angle of pure optimization, this paper obtained the optimal parameters of single cavity and double cavity structure by using the simulated annealing algorithm for single cavity and double cavity of aluminum foam sound absorption structure of systematically optimization design at 100-4000HZ frequency band. Finally, studying effect of increasing the number of cavity on aluminum foam sound absorption properties.
1187
Authors: Yan Bing Zhang, Chun Yu Ren, Xi Zhu
Abstract: In this paper, we designed a FGM which can be used as the cover of underwater target and research its mid-low frequency acoustic characteristic just as reflection and absorption coefficient. Based on transfer matrix method, we research the FGM acoustic reflection and absorption coefficient change with the variation of constituent material property, number of hierarchy, and volume fraction. We found that its reflection and absorption coefficient are determinated by material property and volume fraction, and could be equivalent to multi-layer composite structure with specific number of layers to address acoustic problems. If elastic layer added, both acoustic characteristic and mechanics characteristic could be improved, which contributes to the research and design of structure/acoustic stealth FGM.
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