Non-linear sound absorption analysis, multiscale design and application of metallic fibrous materials

本课题研究高温、高声压环境下金属纤维材料的非线性吸声分析、多尺度设计及应用。该项目旨在开发一种非线性吸声理论，一种金属多孔材料的数值技术，以及一种应用于飞机发动机创新声学衬里的微观和宏观设计策略。在“材料制造--表征--基于性能的结构设计--材料与结构优化”的综合创新方法论的基础上，应用流体力学理论、传热学理论、有限元方法、金属纤维材料制备技术、扫描电子显微镜(SEM)和透射电子显微镜(TEM)微观结构表征、声阻抗管测量等方法，对金属纤维材料的非线性吸声行为进行了表征。研究了微尺度结构参数、高温和高声压对金属纤维材料非线性吸声性能的影响。分析了不同形状的特征单胞在不同柱面纤维束中粘性流体流动的速度场和温度场。基于金属纤维材料微观结构的分形理论表征，考虑高温、高声压的非线性效应，建立了金属纤维材料在高温、高声压环境下吸声性能预测的非线性理论模型和有限元数值模型。在此基础上，建立了非线性理论模型和有限元数值模型，研究了金属纤维声线耦合圆管的降噪效果。揭示了宏观和微观尺度的声能量消耗和转化的机理。与多变量问题的优化策略相结合，将发展一种宏微观尺度的结构设计技术。该项目将为新型金属纤维材料的工程应用，特别是在航空发动机声学衬里设计中的应用提供理论和技术基础和指导。拟议中的项目是由德国和中国申请者合作的项目。两支球队几年来一直保持着密切的合作。通过这个联合项目，应该继续和加强他们的合作。两个团队将在拟议的项目上合作，结合各自的研究优势，促进参与的德国和中国年轻科学家。

This project deals with the non-linear sound absorption analysis, multiscale design and application of metallic fibrous materials in high temperature and high sound pressure environments. The project aims to develop a non-linear sound absorption theory, a numerical technique for metallic porous materials, and a micro- and macro-scale design strategy for the application to innovative acoustic liners in aircraft engines. On the basis of the integrative innovation methodology of 'material manufacturing - characterization - performance-based structural design - optimization of the materials and structures', the fluid mechanics theory, heat conduction theory, finite element method, metallic fibrous material fabrication technique, micro-structural characterization by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM), and acoustic impedance tube measurement approach will be applied to characterize the non-linear sound absorption behavior of metallic fibrous materials. The influences of the micro-scale structural parameters, high temperature and high sound pressure on the non-linear sound absorption property of the metallic fibrous materials will be investigated. The velocity field and the temperature field of the viscous fluid flow in different cylindrical fiber bundles of characteristic unit-cells of various shapes will be analyzed. Based on the fractal theoretical characterization of the micro-structure and the consideration of the non-linear effects of high temperature and high sound pressure, a non-linear theoretical model and a finite element numerical model for predicting the sound absorption property of metallic fibrous materials in high temperature and high sound pressure environments will be developed. Furthermore, a non-linear theoretical model and a finite element numerical model will be established to investigate the noise reduction of the cylindrical tube coupled with metallic fibrous acoustic linear. The mechanisms for the macro-/micro-scale sound energy consumption and transformation will be revealed. In conjunction with the optimization strategy for multiple variables problems, a macro-/micro-scale structural design technique will be developed. This project will provide theoretical and technical foundation and guidelines for the engineering applications of the innovative metallic fibrous materials especially in the design of the acoustic liners in aircraft engines. The proposed project is a cooperation project by the German and the Chinese applicants. Both teams have a close cooperation since several years. Through this joint project, their cooperation should be pursued and strengthened. Both teams will work together on the proposed project, combine their individual research strengths and promote participating young German and Chinese scientists.