用脉冲法研究多孔性材料的声反射
A STUDY OF THE SOUND REFLECTION FROM POROUS MATERIAL BY IMPULSE METHOD
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摘要: 本文提出当脉冲声源和接收点在同一条垂直于材料表面的直线上时,声脉冲从多孔材料反射的研究。由实验入射和反射声脉冲利用DFT计算了反射声波的传递函数。在把材料假设为理想多孔性材料的前提下,理论上可以计算反射声波的脉冲响应。计算中考虑了局部反应和延伸反应材料。通过球面波和平面波计算的比较,提供球面波对反射声波传递函数的影响量。对一多孔材料层,也研究了材料中的反射。Abstract: This paper presents a study of the reflection of sound pulse from porous material in the ease that the impulse sound source and receiver are located on a line perpendicular to the surface of material. The transfer functions of reflected sound wave were calculated from the experimental incident and the reflected sound pulses by use of DPT. The impulse response of reflected sound wave am be calculated theoretically under the assumption of idealized porous material. Both local reaction and extended reaction of the material were taken in the calculations. A comparison of the calculations for spherical wave and plane wave provides a measure of the effect of spherical wave on the transfer function of reflected sound wave. For a layer of porous material the reflections in the material are studied.