| 余佳亮,米琼,毛东兴†.教室梁侧吸声的低频附加吸声效应*[J].,2024,43(4):874-879 |
| 教室梁侧吸声的低频附加吸声效应* |
| Excess low frequency sound absorption of structural beam side arranged absorber in classroom |
| 投稿时间：2023-03-06 修订日期：2024-07-05 |
| 中文摘要: |
| 本文对安装在学校教室中梁侧边的吸声结构在低频产生的特殊吸声现象进行了研究。通过在实际学校教室中,将两种不同深度的吸声结构分别安装于教室的结构梁的侧边,测量获得不同安装条件下的教室内的混响时间,根据赛宾公式反算得到吸声结构在现场的吸声系数,并与其在无规入射条件下的实测吸声系数对比。对比分析结果表明,根据混响时间计算得到的吸声系数在低频段远高于实验室测量得到的结果,表现为低频附加吸声的特点。分析得出了产生低频附加吸声效应的起始频率为房间的高低频转换频率,说明了低频附加吸声的机理为模态声场的影响。提出了用吸声放大系数来定量描述附加吸声效应,给出了其数学表达式,并验证了与实测结果的相符性。 |
| 英文摘要: |
| Special low frequency sound absorption character in classroom was studied when sound absorber was mounted at the sides of structure beams. Absorber with two different depths were installed at the sides of structure beam in classroom, and reverberation times were measured under each kind of absorption configuration. The actual absorption coefficients of absorbers under each situation were calculated with the Sabine formula, and compared with that of random incidence test value. The results show calculated sound absorption was much higher than that measured in random incidence at low frequency, display an excess low frequency sound absorption effect. Further analysis showed the low frequency additional absorption starts at the high-low transition frequency of the room, proved the effect can be explained as room mode theory. An absorption magnificent ratio was defined to quantify excess absorption, and mathematical formula describing relation between the ratio and frequency was derived. Calculated results with the formula are in good agreement with that of measurement. |
| DOI：10.11684/j.issn.1000-310X.2024.04.020 |
| 中文关键词: 低频吸声 附加吸声效应 梁侧吸声 |
| 英文关键词: Low frequency absorption Excess absorption effect Beam-side absorption |
| 基金项目: |
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