建筑和建筑构件低频段空气声隔声的测量及其应用

When measuring airborne sound insulation in buildings and of building elements, it is necessary to measure the sound power of incident on the test specimen and transmitted through by the specimen. The traditional sound pressure method measures the average sound pressure level in the spatial area of the room excluding the edges. This method has a few shortcomings, such as great uncertainty in the low frequency and unfeasibility to measure the sound reduction index of the different elements in the receiving room respectively, as there is not ideal diffuse sound field in the sound source room and the receiving room. We have studied the estimated precision and bias between the conventional sound pressure method and the sound intensity method. While this project will explore the estimated precision and bias between the above two methods based on the modal theory of panel/enclosure further; and then the relationship between the low frequency incident sound power and the average sound pressure level by the different position will be studied, such as the spatial area of the room, the surface closed to the specimen and the corner in the room; finally this project will investigate the principles of the influence of the measurement distance on the pressure-intensity indicator, establish a mathematical model between the absorption and the indicator. The ultimate goal of this proposed project is to enable the measurement of the sound reduction index of the different elements in the receiving room by the sound intensity method, and eventually become a new theory and method of measuring low-frequency sound insulation to overcome the shortcomings for the sound pressure method. The outcome of the proposed project will also have an important impact on the application and evaluation of measuring sound insulation of green buildings.

测量建筑和建筑构件的空气声隔声量时，需要分别测量声源室内被测构件的入射声功率和接收室内被测构件的辐射声功率。传统声压法测量隔声量需要在不包括边界的整个室内空间测量平均声压级，会受声源室和接收室不满足理想扩散声场的影响，在低频处产生较大的不确定度，且不能分别测量接收室内不同构件的隔声量。本研究拟在传统声压法和声强法的精度和偏差对比研究的前期基础上，利用板/闭合空间的模态理论进一步研究声压法和声强法测量低频隔声量的偏差；然后研究在非理想扩散声场条件下，低频入射声功率与室内空间、构件表面和角落等不同位置的平均声压级之间的关系；最后探索测量距离影响声压-声强指示值的规律，建立接收室的吸声量与声压-声强指示值间的数学模型，并实现声强法分别测量接收室内不同构件的隔声量的目的，提出一种新的低频段隔声量的测量理论和方法，以克服声压法的上述缺点。该研究的成果将促进隔声测量技术在绿色建筑评价中的应用。

传统声压法测量隔声量需要在不包括边界的整个室内空间测量平均声压级，会受声源室和接收室不满足理想扩散声场的影响，在低频处产生较大的不确定度，且不能分别测量接收室内不同构件的隔声量。对此，本项目首先研究了传统声压法和声强法的精度和偏差，建议采用声压法减去Waterhouse修正项后与声强法对比，更符合隔声量测量的物理意义，并指出声强法测量隔声量在高频范围的结果不会明显高于声压法，两种方法在高频范围亦不存在比中频范围更大的标准偏差。第二研究了在声源室不同位置测量入射声功率的差异，当测量位置与被测构件较为接近或者处于声源室角落时，声源室声压级的标准偏差可以得到改善。第三研究了声压法和声强法的测量不确定度。结果表明：构件的低频隔声性能对其测量不确定度有较大影响；声强法有较好的低频测量鲁棒性；若构件在低频范围和高频范围分别受阻尼控制作用和吻合作用而产生“低谷”，则其隔声单值量不确定度会比较大。最后，利用声强法测量得到的隔声数据做可视化研究，由于子测量面通常较少，可通过线性插值对测量结果进行处理，得到较好的可视化结果 。