Effect of Surface Modification on the Sound Absorption Behavior of Open Celled Aluminum Foams

2014 ◽  
Vol 783-786 ◽  
pp. 1509-1512 ◽  
Author(s):  
Yun Jie Li ◽  
Yue Lu Ren ◽  
Zhen Dong Li ◽  
Fu Sheng Han
Keyword(s):  
Phase Composition ◽  
Cell Walls ◽  
Sound Absorption ◽  
Flow Resistance ◽  
Aluminum Foams ◽  
Absorption Properties ◽  
Low Frequencies ◽  
Al Foam ◽  
Effect Of Surface ◽  
Al Foams

In the present study, needle like micro-Co3O4 rods were synthesized on the cell walls of open celled Al foam. The microstructure and phase composition of micro-rods and sound absorption properties of resultant samples were characterized. Compared with original Al foams, the modified ones showed enhanced sound absorption capacities, particularly at low frequencies, which were more obvious as the length of Co3O4 rods increased. The improvement is related to increased air flow resistance owing to increased roughness of the cell walls.

Analysis of the Influence of Static Flow Resistance on the Sound Absorption Properties of Aluminum Foam

2012 ◽  
Vol 535-537 ◽  
pp. 1459-1462 ◽  
Author(s):  
Huai Qian Bao ◽  
Ning Zhang ◽  
Xue Gang Hou
Keyword(s):  
Sound Absorption ◽  
Flow Resistance ◽  
Aluminum Foam ◽  
Circular Tube ◽  
Peak Frequency ◽  
Absorption Properties ◽  
Absorption Frequency ◽  
Porous Aluminum ◽  
Static Flow ◽  
Resistance Value

For the complexity of the internal microstructure of porous aluminum foam, on the basis of Rayleigh-Kirchhoff circular tube model, taking viscosity loss and thermal transmission, the paper establishes a simplified theoretical model for sound absorption properties of aluminum foam. The paper also calculates and analyzes the influence of Static flow resistance on the sound absorption properties in the rigidity and cavity backing. The results show that the peak frequency moves to lower with the increasing of the thickness of the air layer. What’s more, there is a direct corresponding relation between flow resistance and the best sound absorption frequency range of aluminum foam. In a reasonable range of flow resistance value, the capability of sound absorption reach optimal, Aluminum Foam won’t have fine sound absorption capability if the value of flow resistance is too big or small.

Synthesis of ZnO micro-rods on the cell walls of open celled Al foam and their effect on the sound absorption behavior

2013 ◽  
Vol 91 ◽  
pp. 242-244 ◽  
Author(s):  
Yuelu Ren ◽  
Kun Wang ◽  
Bo Zhu ◽  
Xinfu Wang ◽  
Xingfu Wang ◽  
...  
Keyword(s):  
Cell Walls ◽  
Sound Absorption ◽  
Al Foam

scholarly journals Al-Based Foams as Permanent Cores in Al Castings: Effect of Surface Skin Thickness and Composition on Infiltration and Core-Shell Bonding

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1715
Author(s):  
Sara Ferraris ◽  
Antonio Santostefano ◽  
Antonio Barbato ◽  
Roberto Molina ◽  
Graziano Ubertalli
Keyword(s):  
Skin Thickness ◽  
Al Alloy ◽  
Strength Increase ◽  
Aluminum Foams ◽  
Gravity Casting ◽  
Acoustic Insulation ◽  
Metallurgical Bonding ◽  
Compression Resistance ◽  
Effect Of Surface ◽  
Al Foams

An emerging and still poorly explored application of aluminum foams is their potential use as permanent cores (inserts) in the casting of aluminum alloys. In this context, Al-based foams can introduce a weight reduction, the obtainment of cavities, a strength increase, the ability to absorb impact energy and vibration, acoustic insulation ability, the possibility to simplify the technological processes (no removal/recycling of traditional sand cores), and finally, they can be fully recyclable. Cymat-type Al foams with thin outer skin were used as permanent cores in Al-alloy gravity casting in the present research. Al-foams were characterized in terms of porosity, density, cell wall and skin thickness, surface chemical composition and morphology, and compression resistance. Cast objects with foam inserts were characterized by means of optical microscopy. The preservation of up to 50% of the initial porosity was observed for foam inserts with higher density. Metallurgical bonding between the foam core and the cast metal was observed in some regions.

scholarly journals Effect of Thickness, Density and Cavity Depth on the Sound Absorption Properties of Wool Boards

2018 ◽  
Vol 18 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Hua Qui ◽  
Yang Enhui
Keyword(s):  
Sound Absorption ◽  
Raw Material ◽  
Wave Tube ◽  
Absorption Coefficients ◽  
Absorption Properties ◽  
Cavity Depth ◽  
Low Frequencies ◽  
High Frequencies ◽  
Standing Wave Tube ◽  
Better Than

Abstract A novel wool absorption board was prepared by using a traditional non-woven technique with coarse wools as the main raw material mixed with heat binding fibers. By using the transfer-function method and standing wave tube method, the sound absorption properties of wool boards in a frequency range of 250-6300 Hz were studied by changing the thickness, density, and cavity depth. Results indicated that wool boards exhibited excellent sound absorption properties, which at high frequencies were better than that at low frequencies. With increasing thickness, the sound absorption coefficients of wool boards increased at low frequencies and fluctuated at high frequencies. However, the sound absorption coefficients changed insignificantly and then improved at high frequencies with increasing density. With increasing cavity depth, the sound absorption coefficients of wool boards increased significantly at low frequencies and decreased slightly at high frequencies.

Synthesis of a multicomponent silica aerogel-containing nanocomposite for efficient sound absorption properties

2021 ◽  
pp. 096739112098574
Author(s):  
Mansoureh Hamidi ◽  
Parvin Nassiri ◽  
Homayoon Ahmad Panahi ◽  
Lobat Taghavi ◽  
Saeed Bazgir
Keyword(s):  
Silica Aerogel ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Transmission Loss ◽  
Pressure Level ◽  
Tube Model ◽  
Absorption Properties ◽  
Low Frequencies ◽  
High Frequencies ◽  
Optimum Sample

In this study, the sound properties of four types of nanocomposites have been investigated. To this end, the prepared samples were measured by the impedance tube model BSWA-SW 422, SW477. It was found that the Sound Absorption Coefficient (SAC) of all samples was increased at high frequencies relatively well. The highest SAC at medium and low frequencies was related to the nanocomposite D. The results of sound Transmission Loss (TL) of nanocomposites showed that the TL value for the nanocomposite D (optimum sample) was higher at all frequencies compared to other nanocomposites. The results confirmed that adding organic and mineral materials to the silica aerogel (SA) simultaneously improves its sound properties. By measuring the Sound Pressure Level (SPL) around the enclosure without optimum sample and with optimum sample in the four sound ranges, we found that using nanocomposite D can significantly reduce the noise. According to this study, SA/polyester nonwoven layer/pan nanofibers/nanoclay nanocomposite (nanocomposites D) have great sound absorption properties, which can be used in different environments.

Investigation of AC8A Scrap-Recycled Aluminum Foams

2014 ◽  
Vol 894 ◽  
pp. 134-137
Author(s):  
Seksak Asavavisithchai ◽  
Natthida Jareankieathbovorn ◽  
Areeya Srichaiyaperk
Keyword(s):  
Casting Process ◽  
Polyurethane Foams ◽  
Aluminum Foams ◽  
Major Drawback ◽  
Pressure Infiltration ◽  
Open Cell ◽  
Al Foam ◽  
The Cost ◽  
Recycled Material ◽  
Al Foams

Open-cell Al foam has outstanding properties which are suitable for functional applications. However, a major drawback for widespread employment of Al foam is its high relative cost which can be several times higher than conventional metals. To reduce the cost, a recycled material waste is constructively used instead of expensive base metal. The present study aims to fabricate economical open-cell Al foams using AC8A alloy scrap from lathe machines. The Al foams were fabricated through pressure infiltration casting process at which the cellular pattern was made from commercial reticulated open-cell polyurethane foams with the pore size of 12 ppi. The compressive strength and microhardness of scrap-recycled Al foams are higher than those of pure Al foam. The increase in foam mechanical properties resulted from the change in foam microstructure as the formation of Si hard phase in Al matrix. The strength and microhardness of the foams increase with increasing scrap contents.

Sound Absorption Properties of Al Foam

2005 ◽  
pp. 468-471
Author(s):  
Sang Youl Kim ◽  
Soo Han Park ◽  
Yong Su Um ◽  
Bo Young Hur
Keyword(s):  
Sound Absorption ◽  
Absorption Properties ◽  
Al Foam

Sound Absorption Properties of Al Foam

2005 ◽  
Vol 486-487 ◽  
pp. 468-471 ◽  
Author(s):  
Sang Youl Kim ◽  
Soo Han Park ◽  
Yong Su Um ◽  
Bo Young Hur
Keyword(s):  
Sound Absorption ◽  
Aluminum Foam ◽  
Air Gap ◽  
Absorption Property ◽  
Absorption Properties ◽  
Al Foam ◽  
High Sound ◽  
Very High

Aluminum foam with 0.2 g/cm3 density showed a good sound absorption property at frequencies higher than 2000 Hz. Compressed aluminum foam with an air gap of 50 mm or higher exhibited a very high sound absorption property near 400 Hz.

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