Experimental Research And Analysis Of Acoustic Property For Aluminum Foam Composite Structure

Aluminum foam is the advancing material in recent years. It is structural materials with low densities and high strength ratio and function material having many physical properties, such as shock absorption, damping, sound absorption and so on. But it's not suitable to be used as separate structure for sound insulation and sound absorption because of its low performance of mechanical strength. The use of composite structure is a very good solution to this problem. The attention is payed increasing of aluminum foam with composite structure.Based on the sufficient analysis of development at home and aboard about aluminum foam with composite structure, the influencing factors of sound absorption aluminum foam are analyzed, the effect of material thickness to absorption aluminum foam are researched, its sound absorbing performance are improved by increasing cavity behind the material at low frequency; a brief explanation are made of the aluminum foam of damping performance, the insulation property of richly structure are introduced, the acoustic model of three layers are established, and the influencing factors of sound insulation property of composite construction are analysed. Sound transmission loss of the compound board mathematics models are established. Then the relation is abtained among the sound insulation influence of the aluminum foam compound board and material thickness, modulus ratio and dissipation factor of aluminum foam. The sound insulation influence coefficient of the aluminum foam compound board with different thickness ratio and dissipation factor of aluminum foam are abtained through the sound numerical analysis by Matlab. Intrinsic mode is analysed by ANSYS for aluminum foam and complex structure, the results show that the sound insulation property is better at a low frequency and high frequency.Finally the experiment testing of existing samples are carried out by four-microphone method, the analysis data among the test data are compared. The results show that theoretical analysis and experimental data is consistent. Increasing-falling-increasing is the trend of sound insulation with the increasing of frequency. The low of sound insulation loss appeared at critical in frequency, then rapid increase, the effect of sound insulation is perfect in total.