微穿孔板复合对二次余数扩散结构扩散性能影响研究

A study on diffusion properties of the quadratic residue diffuser structure composited with micro-perforated sheet

扩散吸声结构(Diffsorber)能应用于室内外声品质的改善,具有很好的研究意义和应用前景。微穿孔复合二次余数扩散(Quadratic residue diffusers,QRD)结构能显著提高低频吸声性能,但复合对扩散性能的影响未见报道。本论文对QRD结构及其与厚度为0.6 mm,穿孔率为1%、2%、3%的微穿孔板复合结构的扩散性能进行测试,通过计算得出相应的反射声能极坐标图和扩散系数。研究结果表明,微穿孔复合QRD结构在中低频特别在结构自身共振频率范围内具有良好的扩散性能,扩散系数在0.8到0.95之间,随着频率增加,复合结构的扩散性能有下降的趋势,同时由于微穿孔板的吸声性能,复合后结构的空间反射声能普遍降低5 dB左右。

Diffsorber can be applied to improve the quality of indoor and outdoor sound, it has good research significance and application prospects. The quadratic residue diffusers （QRD） structure eomposited with micro-perforated sheet can significantly improve the performance of low-frequency sound absorption, but the diffusion properties about it have seldom been reported. This paper carried out a test to the QRD structure and its composite smacture with 0.6 mm-thickness, perforated percentage of 0.1%, 0.2%, 0.3% microperforated-panel, obtained polar coordinate diagrams and diffusion coefficient of different structure by calculating. The results show that the QRD structure composited with micro-perforated sheet has good diffusion properties in the low frequency （especially in structure＇s resonance frequency range）. The diffusion coefficient is between 0.8 and 0.95, and the diffusion properties of the composite structure declines when the frequency increases. Meanwhile, due to sound absorption performance of the micro-perforated sheet, the structure space reflected sound generally reduces by about 5 dB after composited with micro-perforated sheet.