基于虚拟方法的混响箱设计及实验验证

Design of Reverberation Chamber Based on Virtual Algorithm and Experimental Verification

混响箱常用于材料隔声、吸声实验研究中,因此混响箱的设计对于实验的可靠性有着重要影响.混响箱的传统设计都是基于混响声场特性,其效率较低,可靠性也较差.为此,设计了一种复合结构的混响箱模型,通过统计能量分析(SEA)法对复合结构的隔声特性进行了仿真分析,用边界元方法(BEM)模拟混响箱内的声场分布,依据仿真结果对模型进行优化,最终获得具有足够隔声量和均匀声场的混响箱模型.对基于仿真模型制作的混响箱进行隔声实验,结果表明,在400,Hz以上频率范围内,混响箱的隔声量高于50,dB;混响箱内不同位置的声压级相差不超过3.5,dB.镁合金板的隔声实验结果与质量定律及统计能量分析所得结果吻合良好.可见,采用复合结构箱体能实现良好的隔声效果,借助于统计能量法和边界元方法对混响箱进行设计是行之有效的.

Experiments on sound insulation and sound absorption of materials are always carried out with reverberation chamber.So the design of the reverberation chamber has an significant effect on the reliability of such experiments.Traditional designs of reverberation chambers are based on the characteristics of reverberative sound field,which has a low efficiency and reliability.To solve the problem,a sandwich structure was used to construct the reverberation chamber.Sound reduction of the structure and sound distribution inside the reverberation chamber were simulated with statistical energy analysis （SEA） and boundary element method （BEM）,respectively.The model was optimized so as to have a good sound insulation performance and achieve a uniform sound field.After manufacturing the reverberation chamber based on the simulated model,experiments were conducted to check the reverberation chamber.It is indicated that the noise reduction above 400 Hz is larger than 50 dB,and the difference in sound pressure level at different locations inside the chamber is smaller than 3.5 dB.The sound insulation characteristics of magnesium alloy obtained from experiment agree well with mass-law and SEA simulation,respectively.The SEA and BEM are feasible to be used for reverberation chamber design,and the sandwich structure has a good performance in sound insulation.