波形拟合水声构件插入损失测量方法研究

发布时间：2018-06-07 15:02

本文选题：声学测量 + 波形拟合　；参考：《中国测试》2016年12期

【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 m×1.4 m×1.1 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 k Hz。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。
[Abstract]:In order to eliminate the interference of the boundary reflection wave on the received signal in the low frequency measurement of underwater acoustic material, the acoustic range difference between the direct wave and the reflected wave is increased by shortening the propagation distance of the transmitted signal, and an effective single direct wave is obtained. A complete period waveform is obtained by fitting the single direct wave with Matlab, and the amplitude of the wave is read as experimental data. The experiment was carried out in a steel tank of 4 m 脳 1.4 m 脳 1.1 m with a water depth of 0.8 m. The sample is a hollow FRP tube with an external diameter of 30 cm and a thickness of 1 cm. The measuring frequency is 830 kHz. The transmission coefficient of the sample is calculated after the measurement is completed, and the insertion loss of the sample is obtained. The experimental results show that the relative errors of the measured values are less than 10, the uncertainty of the measurement results is 5, the measured values are in good agreement with the theoretical values, and the validity of the method is proved. This method is suitable for the measurement of acoustic parameters of materials in non-free sound field. It is simple, rapid and effective, and has certain practical value for the measurement of underwater acoustic properties of large sample materials.
【作者单位】：中国计量大学计量测试工程学院;
【基金】：国家自然科学基金项目(11474259)
【分类号】：TB564

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