CompositesWorld
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37 CompositesWorld.com NEWS N E W S N S N E W S E N W S W Processes and materials Historically dominant, hand layup and auto- clave cure of prepreg remains the most-used method for producing composite engine components. Filament winding also has a long history, but a much smaller role in aeroengines, as the method used to fabricate aramid fber containment belts that surround fan cases. Like fabricators of other aircraft structures, engine builders have long sought to drive down manufacturing costs and maximize production output and efciency. Tat quest has led the former to develop auto- mated tape laying (ATL), automated fber placement (AFP) and infusion processes for large primary structures. But the latter have been drawn to methods more readily appli- cable to relatively small but more complex engine parts. A case in point is CFM's LEAP 1 (see photo at right), expected to enter service later this decade. Individually placed, autoclave-cured prepreg plies have been replaced in its fan blades by 3D braided preforms processed by RTM. Tis strategy reduces composite part complexity and yields a dramatically shorter cure cycle, cutting the cost per unit of weight saved. Fig. 8 illustrates that autoclave/prepreg and RTM processes (the latter accounting for nearly 30% of production) will continue to dominate the market over the forecast. Although RTM has proven to 7,000,000 6,000,000 5,000,000 4,000,000 3,000,000 2,000,000 1,000,000 0 Annual Composite Requirements (lb) 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 Others Williams International Eurojet Engine Alliance International Aero Engines Honeywell-Allied Signal Pratt & Whitney Rolls-Royce General Electric CFM International FIG. 7 Advanced Aeroengine Composites Demand by OEM Data for projected turbofan engine production by individual OEMs indicate that CFM International (Melun, France) and one of its parent companies, GE (Evendale, OH, US), together, will own a 72% market share. be the most adaptable processing alternative, multiaxial compres- sion molding is emerging as a viable means to mold some smaller components, including fan platforms and, perhaps more interest- ingly, thrust reversers — an application historically dominated by suppliers based in Japan. In terms of fber reinforcements, our study found that glass, carbon and aramid fbers will continue to be incorporated into engine component laminates. Aramid, as noted, will reinforce fan containment cases. Glass fbers, currently, are used primarily in CFM's LEAP engine takes of on a modifed 747 fying testbed as the company's extensive ground and fight test certifca- tion program continues. Source | CFM International Aeroengines, 2014-2023