Ferrous fibre network materials for jet noise reduction in aeroengines - Part I: Acoustic effects

A study was conducted to analyze highly porous metallic materials made by bonding ferrous fibers for constructing network materials to reduce jet noise in aeroengines. These materials can be used to construct various network architecture, such as void content, void connectivity and scale, which are important for jet noise reduction. The network materials were produced by sintering in vacuum, for about 1-2 hours at 1200°C. Graded density modules of the stainless steel were produced by separately sintering thin sheets, using different consolidation pressures, and then bonding them together. X-ray microtomography was used to analyze properties, such as yield strength and resistance to creep and fatigue. A Pegasus HP E-Start engine was used for the experiment. Result show that significant sound absorption can be achieved across the complete frequency range of interest, within fiber network materials