联合扩散场激励与近场声全息重建的建筑构件隔声测量方法

Sound insulation measurement of building components combining diffuse acoustic field excitation and near-field acoustic holography reconstruction

提出了一种联合扩散场(DAF)激励与近场声全息(NAH)辐射声强重建的建筑构件空气声隔声测量方法。该方法首先通过DAF激励构件振动并获取入射声功率,然后利用NAH技术从辐射声压场中重建构件表面高空间分辨率的法向声强分布,最后根据声强分布来计算辐射声功率和定位辐射热区,从而实现构件隔声量和隔声缺陷测量。隔声室实验研究表明,在测试距离和采样间距均为0.04 m的条件下,该方法测量的隔声量与声压法的误差在100~5000 Hz频带小于3.3 dB,在250~3150 Hz频带小于1.3 dB,对圆孔(直径8 mm)和矩形缝(长80 mm、宽3 mm)的定位精度高达厘米级;同时,该方法在一定混响和背景噪声影响下的稳定性较强,接收室混响时间从1.0 s增至3.4 s(步长0.6 s)以及信噪比从10 dB降至0 dB(步长5 dB),隔声量测量误差分别在0.8 dB和0.3 dB以内,缺陷定位误差在0.037 m和0.035 m以内。所提方法有助于提高实验室中建筑构件隔声特性的测量能力,同时对接收室测试环境具有较强的鲁棒性。

A method for measuring the airborne sound insulation of building components combining diffuse acoustic field(DAF)excitation and near-field acoustic holography(NAH)radiation intensity reconstruction is proposed.In this method,DAF is first used to excite the vibration of the component and obtain the incident sound power,then the normal sound intensity distribution with high spatial resolution on the surface of the component is reconstructed from the radiation sound pressure field using NAH,and finally,according to the sound intensity distribution,the radiated sound power is calculated and the radiation heat areas are located,so as to realize the measurement of sound insulation and sound insulation defects of components.The experimental research in a sound insulation room shows that under the condition that the test distance and sampling interval are both 0.04 m,the error of the sound insulation measured by this method compared to the sound pressure method is less than 3.3 dB in the 100–5000 Hz frequency band and less than 1.3 dB in the 250–3150 Hz frequency band,and the positioning accuracy of round holes(diameter:8 mm)and rectangular slots(length:80 mm,width:3 mm)is up to the centimeter level.The method has strong stability under the influence of certain amount of reverberation and background noise.When reverberation time in the receiving room increases from 1.0 s to 3.4 s(step size:0.6 s),and the signal-to-noise ratio decreases from 10 dB to 0 dB(step size:5 dB),the sound volume measurement errors are within 0.8 dB and 0.3 dB,and the defect location errors are within 0.037 m and 0.035 m.The proposed method helps to improve the measurement capability of sound insulation characteristics of building components in the laboratory,and it is robust to the receiving room test environment.