结构隔声测试方法实验研究

结构隔声测试在结构声学设计、环境噪声控制、建筑声学和国防工业等领域应用广泛。本文在引入边缘衍射时域分离技术和虚拟仪器测试技术的基础上,以铝板为样品,以半消声室为测试场所,对自由场法在结构隔声测试领域中的应用开展了实验研究,并对边缘衍射、测试脉宽、系统增益和平均时间等因素对测试结果的影响进行了理论分析。此外,为改善测试信噪比和系统频响带宽特性,还分别提出了样品等效放大技术和组合宽带发射技术。实验研究结果表明:在有效带宽内,隔声测试结果与理论值吻合较好,平均偏差仅为0.05dB左右,测试精度较高。自由场法不需要专门的隔声室设施,实现了非隔声室环境条件下的结构隔声测试,测试结果准确可靠,特别适用于工程现场测试,值得尝试与推广。

Experimental Study of Measurement Method for Insulating Structure-borne Sound

Structure-borne sound insulation measurement is widely applied to acoustic structural design,environment noise control,architectural acoustics,and national defence industry,etc.Using the time domain separation technology through edge diffraction and virtual instrument test technology,we do the experimental study of how the free-field method is applied to structure-borne sound insulation measurement.In the experimental study,we use aluminum panel as test place.On this basis,we conduct the theoretical analysis of the influence of edge diffraction,pulse width of test signal,system gain,and average time,on the measurement results.Furthermore,we propose the sample equivalent enlargement technique and combinatory broadband transmission technique so as to improve signal to noise ratio measurement and frequency response bandwidth properties.The results show that within the effective bandwidth,sound insulation measurement results agree well with the theoretical value,the average difference being only 0.05dB.The free-field method measures structure-borne sound insulation without requiring a special-purpose sound insulation chamber.Its measurement results are precise and reliable,especially suitable for field engineering test.