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边缘效应对混响室法测量吸声系数影响的研究中,大多是通过改变试件面积和排列方式来从侧面研究边缘效应,一直以来缺少对边缘效应影响的直接研究。本研究以玻璃棉为例对边缘效应的影响进行直接研究,具体研究方法是在标准混响室内,通过混响室内设置的升降平台的上下移动,可以得到材料表面高出或与地面平齐的不同情况,以达到存在或消除试件边缘效应的效果,进行对比研究,得到不同状况下相应的混响时间,计算出在不同情况下的吸声系数。研究结果表明,对于玻璃棉来说,在高频段上边缘效应使得其吸声系数有所提高,但不是导致吸声系数大于1的唯一因素,从总体上来看,边缘效应的影响有限。
In the researches on the influence of edge effect on the measurement of sound absorption coefficient in reverberation chamber, most of them study the edge effect from the side by changing the area and arrangement of the specimen. There is a lack of direct research on the influence of edge effect. In this study, glass wool as an example of the edge effect of a direct study, the specific method of research is in a standard reverberation chamber, through the reverberation chamber set up and down the platform up and down movement, you can get the material surface above or flush with the ground Different situations, in order to achieve or eliminate the effect of the edge of the specimen effect, make a comparative study, get the corresponding reverberation time under different conditions, calculate the sound absorption coefficient in different situations. The results show that for glass wool, the edge effect at high frequency increases the sound absorption coefficient, but it is not the only factor that causes the sound absorption coefficient to be greater than 1. Generally speaking, the influence of edge effect is limited.