多孔材料吸声计算的空间随机阵列振动系统等效模型

Porous material is the most widely used sound-absorbing material now. So far because of the complex sound absorption mechanism, there are no very mature calculation methods to analyze its sound absorption performance and no theories for the selection, analysis and design of the porous sound absorbing material. Simple reasonable equivalent model is the precondition of porous material acoustics theoretical arithmetic. This project is to explore the absorption mechanism of porous material, and spatial random vibration system equivalent model is proposed on the basis of energy equivalence. Sound energy loss of the porous material caused by various sound-absorbing factors is calculated and is equivalent to the mechanical energy loss of the vibration system. The space topology structure of the porous material is got through the three-dimensional reconstructing, its space statistical properties is studied, and the equivalent model of the mass-spring-damping vibration system of spatial random array is established. The equivalent relationship between the boundary conditions and load of the porous sound-absorbing material is studied, and the mechanical energy loss of the equivalent model is calculated to analyze the sound absorption performance of the porous material. The equivalent model of the vibration system of the sound-absorbing material proposed is verified and improved by the impedance tube method. The proposed method is useful for the research of the acoustics theoretical model of the porous material. This method can be extended to other application fields, just like the vibration and impact of the porous material. So this project has important theoretical value and application prospect.

多孔材料是目前应用最广泛的吸声材料，由于吸声机理复杂，至今没有很成熟的计算方法分析其吸声性能，不能很好地为多孔吸声材料的选型、分析及设计提供理论支持。建立简单合理的等效模型是进行多孔材料声学理论计算的前提。本项目探索多孔材料的吸声机理，基于能量等效的思想，提出多孔材料空间随机阵列振动系统等效模型。计算多孔材料各种吸声因素造成的声能损失并等效为振动系统的机械能损失；对多孔材料进行三维重构得到空间拓扑结构，研究其空间统计特性，建立空间随机阵列的质量-弹簧-阻尼振动系统等效模型，并研究多孔吸声材料的边界条件与载荷的等效，计算等效模型的机械能损失以分析多孔材料的吸声性能；采用阻抗管测试法对所提出的吸声材料振动系统等效模型进行验证和完善。本项目提出的方法对多孔材料声学理论模型的研究提供技术支持，其思路可扩展到多孔材料振动、冲击等其它应用领域。因此本项目具有重要的理论价值和应用前景。

多孔材料是目前应用最多的吸声材料，由于吸声机理复杂，至今没有很成熟的计算方法分析其吸声性能，不能很好地为泡沫金属材料的选型、分析及设计提供理论支持。建立简单合理的等效模型是进行多孔材料声学理论计算的前提。.本项目研究各种能量等效方式，将多孔泡沫金属各种吸声因素造成的能量损失等效为机械振动系统能量损失。首先将单孔剥离出来，建立泡沫金属代表单元的数值模型，等效成单质量-弹簧-阻尼系统，研究各相关参数对吸声能量的影响，阐明了吸声方式和声能量损失之间的耦合关系。采用空间CT技术对泡沫金属进行图像扫描，利用逆向工程软件进行三维几何模型重建，对孔的大小和排列方式进行统计建模，建立空间随机阵列系统。考虑结构、流场、温度场和声场的多耦合问题，对空间随机阵列振动系统的吸声性能进行分析，对不同参数的吸声材料试件进行多次测试，根据测试结果进行等效模型及算法的修正。最终本项目建立了简易高效的泡沫金属声学等效模型，简化了泡沫金属吸声性能的复杂计算，为多孔材料吸声问题提供一定的理论指导和工程参考。本项目提出的方法可扩展到泡沫金属振动、冲击等其它应用领域。因此本项目具有重要的理论价值和应用前景。