作者：吴黎卓, 王月兵, 曹永刚

作者单位：中国计量大学计量测试工程学院, 浙江 杭州 310018

关键词：声学测量;波形拟合;插入损失;声学构件

摘要：

为消除水声材料在低频测量时边界反射波对接收信号的干扰，通过缩短发射信号的传播距离来提高直达波与反射波的声程差，得到一段有效的单一直达波。用Matlab拟合这段单一直达波，得到一个完整周期的波形，读取其幅值作实验数据。该实验在一尺寸为4 m1.4 m1.1 m的钢体水箱中进行，水深0.8 m。试样为一外径30 cm，厚1 cm的空心玻璃钢圆管，测量频率为8～30 kHz。对有无试样两种情况下完成测量后进行透射系数计算，得到试样的插入损失。实验结果表明：测量值相对误差均小于10%，测量结果的不确定度5%，测量值与理论值具有较好的一致性，证明该方法的有效性。本方法适用于非自由声场环境下材料声学参数的测量，具有简单、快速、有效的特点，对大试样材料的水声性能测量有一定的实用价值。

Study on testing method of insertion loss of underwater acoustic structure based on waveform fitting

WU Lizhuo, WANG Yuebing, CAO Yonggang

College of Metrological Technology and Engineering, China Jiliang University, Hangzhou 310018, China

Abstract: In order to eliminate the interference of the boundary reflection wave to the received signal in the low frequency measurement of the underwater acoustic material, the transmission distance of the signal was shortened to expand the acoustic path difference between direct wave and reflected wave to get an effective single wave. The direct wave was intercepted and fit with Matlab to get a complete cycle of the waveform, and amplitude was recorded as experimental data. This method was carried out in a steel water tank with the size of 1.1 m× 1.4 m ×4.0 m, and the water was 0.8 m deep. The sample was a hollow glass reinforced plastic circular pipe with the outer diameter of 30 cm and the thickness of 1cm. The measuring frequency was 8-30 kHz. After measuring two cases where there's sample and there wasn't sample, the insertion loss of the sample was calculated, and the validity of the method was verified by comparing the theoretical value with the measured value. Experimental results show that the relative errors of the measured value are all less than 10%, and the uncertainty of the measurement result is less than 5%. Measurements and theoretical values are coherent, proving validity of the method. The method is suitable for measuring the non-environmental material free field acoustic parameters. It is simple, fast and effective. It is of great practical value to the acoustic performance measurement of large sample materials.

Keywords: acoustic measurements;waveform fitting;insertion loss;acoustic member

2016, 42(12): 29-33  收稿日期: 2016-06-19;收到修改稿日期: 2016-08-05

基金项目: 国家自然科学基金项目（11474259）

作者简介: 吴黎卓(1990-),男,浙江诸暨市人,硕士研究生,专业方向为仪器仪表工程。

参考文献

[1] 李建龙,闫孝伟,孔祥东. 水声无源材料插入损失测量时反聚焦方法[J]. 声学学报,2014,39(2):170-176.
[2] 李水,缪荣兴. 水声材料声性能自由场测量技术研究[J]. 计量学报,1999,20(4):308-313.
[3] 李水,沈建新,唐海淸,等. 水声材料低频声性能的驻波管测量[J]. 计量学报,2003,24(3):221-224.
[4] 郑士杰,袁文俊,缪荣兴,等. 水声计量测试技术[M]. 哈尔滨:哈尔滨工程大学出版社,1995:410-424.
[5] 李水,罗马奇,范进良,等. 水声材料低频声性能的行波管测量[J]. 声学学报,2007,34(4):349-355.
[6] INGARD U, BOLT R H. A free field method of measuring the absorption coefficient of acoustic materials[J]. Acoust Soc Am,1951,23(5):509-516.
[7] SIDES D J, MULHOLLAND K A. The variation of normal layer impedance with angle of incidence[J]. Sound Vib,1971(14):139-142.
[8] 李水,缪荣兴. 水声材料性能的自由场宽带压缩脉冲叠加测量[J]. 声学学报,2000,25(3):248-253.
[9] ALLARD J F, SIEBEN B. The measurement of acoustic impedance at oblique incidence with two microphones[J]. Sound Vib,1985(101):130-132.
[10] TAMURA M. Spatial fourier transform method of measuring reflection coefficients at oblique incidence. I:Theory and numerical examples[J]. Acoust Soc Am,1990, 88(5):2259-2264.
[11] 声学、水声材料样品插入损失和回声降低的测量方法:GB/T 14369-1993[S]. 北京:中国质检出版社,1993.