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AK Steel

Aircraft Manufacturer Chooses PAEK Material for Lightweighting

WEST CONSHOHOCKEN, Pa.–For the development of efficient and durable aircraft floor brackets in its new regional jet ARJ21, COMAC (Commercial Aircraft Corporation of China, Ltd.) uses a combined material and service offering from Victrex. Additional services provided by Victrex, beyond supplying high-performing Victrex^TM PAEK polymers, included simulation analysis, tools for design optimization, and on-site processing support. As a result, greater design freedom, easier manufacturing, and less weight compared to traditionally used aluminum led to the replacement of the metal, according to Victrex.

COMAC's ARJ21 (Advanced Regional Jet for the 21st Century), a type of turbofan jet, is a short- to medium range regional jet. Within the ARJ21, internal loads are supported by various systems, including structural beams. Floor brackets are positioned on these beams to provide support within a gap between the loaded beams and the aircraft flooring above. Typically, these brackets would be manufactured in aluminum. The new solution is reported to promote increased production efficiency via rapid injection molding of the part, and to contribute to higher efficiency of the regional jet through weight savings and design improvements that simplify the installation process.

"Today, weight reduction, resulting in increased fuel efficiency, is absolutely essential and [a] critical success factor," said Dr. Bai Jie, brackets team leader at COMAC. "This is common knowledge within the aerospace industry, but the full potential and processing efficiency of high-performing polymers are not. As a consequence, we have received support from Victrex as the PEEK experts with material and manufacturing knowledge. During the design process, for example, their technical team delivered extensive and valuable support."

Victrex provided, as part of its extended services, the simulation analysis, the tools for design optimization, and on-site solutions whenever processing challenges arose. In engineering terms, each of the brackets has a loading capacity of up to 6,000N, a working temperature range of -55°C – 135°C (-67°F – 275°F), and meets the FAR 25.853 requirements for flame, smoke, and toxicity. Each bracket is also lightweight (30 percent less weight than a corresponding aluminum bracket) and is a viable replacement for the same part manufactured in metal.

The distortion tolerance of less than 0.2mm (0.008 in) is considered optimal for installation in the case of the ARJ21 aircraft. Moreover, the floor brackets are extremely durable and offer an economical 30-year life-cycle, in an industry where safety and reliability are absolute prerequisites.

Each of the aircraft floor brackets used in COMAC's new regional jet ARJ21 is reported to be 30 percent lighter than a corresponding aluminum bracket and meets FAR 25.853 requirements for flame, smoke, and toxicity. The brackets are made of Victrex PAEK polymer. Photo courtesy of Victrex.