Tendencies of using and quality improving products made of fibrous metal composites for structural elements of power engineering under environmental conditions

This paper discusses the relevance of a composite material based on a titanium alloy reinforced with fibers of silicon carbide. The development trends are given for the production of Ti-SiC composite material both abroad and in Russia. Ways to improve the quality of manufactured products from Ti-SiC in the development of heat-stressed parts made of fiber-reinforced metal composites for power engineering in terms of the environment are defined in this paper.

Fractal Model for Acoustic Absorbing of Porous Fibrous Metal Materials

To investigate the changing rules between sound absorbing performance and geometrical parameters of porous fibrous metal materials (PFMMs), this paper presents a fractal acoustic model by incorporating the static flow resistivity based on Biot-Allard model. Static flow resistivity is essential for an accurate assessment of the acoustic performance of the PFMM. However, it is quite difficult to evaluate the static flow resistivity from the microstructure of the PFMM because of a large number of disordered pores. In order to overcome this difficulty, we firstly established a static flow resistivity formula for the PFMM based on fractal theory. Secondly, a fractal acoustic model was derived on the basis of the static flow resistivity formula. The sound absorption coefficients calculated by the presented acoustic model were validated by the values of Biot-Allard model and experimental data. Finally, the variation of the surface acoustic impedance, the complex wave number, and the sound absorption coefficient with the fractal dimensions were discussed. The research results can reveal the relationship between sound absorption and geometrical parameters and provide a basis for improving the sound absorption capability of the PFMMs.