高声强下穿孔板覆盖多孔材料层结构的吸声机理研究

A porous layer covered by a perforated facing is a typical passive sound absorbing construction, with great potentials in an adversed environment of high sound intensities. In order to provide theoretical fundamentals for this type of sound absorbing construction in pratical applications, Our research will concerns mainly with theoretical and experimental study on such construction at high sound intensity in normal incident. From the theoretical aspect, we intend to build up a surface acoustic impedance model, taking into account nonlinear characteristics of both perforated plate and porous layer, as well as physical mechanism of their coupling. From experimental aspect, we will work on the validation of our theoretical models. Experimental investigation will be systematically conducted on samples with different parameters in a high sound intensity impedance tube capable of reaching high sound pressure levels in the range of 120dB to 160dB. Based on both theoretical and experimental work, we will further discuss the design of broad-band, high-sound-absorption and stable construction with optimized of parameters of porous layer, perforated facing and backing cavity.

穿孔板覆盖多孔材料层结构是一种典型的被动式吸声结构,其在高声强环境下具有良好的应用潜力。本项研究主要针对这类结构在高声强正入射下的吸声机理开展理论与实验研究，旨在为该类吸声结构的实际应用提供理论基础。理论上，尝试建立这类结构在高声强下的表面声阻抗预测模型，模型中同时考虑穿孔板和多孔材料层的非线性特性，以及二者间的耦合对结构非线性吸声行为影响的物理机制，并讨论材料层与穿孔板参数对其的影响。实验方面，在高声强阻抗管（声压级达120-160dB）内对不同参数吸声结构样本开展系统的实验，以检验理论模型的正确性，同时掌握这类吸声结构的非线性特性。在理论和实验研究的基础上，进一步探讨高声强下宽带、高吸声、稳定的吸声结构的设计，包括讨论多孔材料层、穿孔板和背腔深度等参数的选择，以优化该类结构在高声强下的吸声性能。

穿孔板覆盖多孔材料层结构是一种典型的被动式吸声结构，其在高声强环境下的吸声降噪方面具有良好的应用潜力。本项目针对高声压级法向入射下穿孔面板覆盖刚性骨架多孔材料复合结构的吸声问题，提出了一个预测模型，该模型同时考虑穿孔板和多孔材料的非线性以及二者间的干涉效应。对穿孔板紧贴多孔层和穿孔板与多孔层间留空气层缝隙两种条件，测试了复合结构吸声性能随入射声压级变化的关系，相应的理论预测结果与实验结果吻合较好，验证了所提模型的有效性。同时结果显示穿孔板与多孔层间的空气缝隙不仅会影响结构的线性声阻抗，也会影响结构的非线性声阻抗和吸声特性，这一影响在设计高声强环境下的该类吸声结构应予以考虑。进一步，本项目对该类吸声结构的非线性吸声特性进行了一些讨论，以提供提高该类结构在高声压级下吸声性能的一些指导准则。