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

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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.