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The 27-county Southwestern Ohio Aerospace Region is nationally-recognized for its manufacturing expertise. In 2014, the region was one of 12 recipients of a “manufacturing communities” designation that puts local organizations front-of-the-line for federal funding to support the aerospace parts and products manufacturing industry.
GE Aviation is at the forefront of a new materials technology that company leaders say will revolutionize aircraft manufacturing along with advances in additive manufacturing processes.
The technology, ceramic matrix composites, is essentially a made-up material, consisting of microscopic fibers assembled together from multiple advanced materials. The combined materials have new and different properties than they would separately.
Specifically, GE is developing jet engine components made from ceramic matrix composites containing silicon carbide ceramic fibers and ceramic resin that are lighter weight, more durable and can withstand hotter temperatures than their metal substitutes, said Jon Blank, chief of engineering for GE Aviation’s CMC laboratory in Evendale.
As a result, new engines are in the pipeline that will be more fuel efficient and last longer than GE’s current engines on the market, Blank said. A more reliable engine benefits travelers and airlines relying on engines always ready for takeoff, he said.
“It gives our product and our engine applications the capability that sets our engines apart,” he said.
When the Wright brothers first started, they made planes from wood, Blank said. The revolutionary next step was making planes out of metal alloys, which allowed aircraft to go higher, faster and travel longer and more efficiently, Blank said. Composites represent the next major advancement in materials, he said.
“The CMC technology is revolutionary because it will really change the way current engines perform because you have gains from so many different fronts,” said Francesco Simonetti, associate professor of aerospace engineering for University of Cincinnati, a research partner with GE Aviation.
Evendale-based GE Aviation will introduce ceramic matrix composites for the first time on its next commercial jet engine, the LEAP, launching next year. High pressure turbine shrouds in the hot section of the engine will be made from the new composite material. Then GE will spread ceramic composites to more parts of the engine after that for the GE9X, which will debut by 2020.
GE has come up with a secret recipe for ceramic matrix composites that Blank says gives the aerospace manufacturer a competitive edge. How the microscopic fibers are put together—whether they’re woven, stacked or laid side-by-side—along with the matrix that holds the fibers together and special coatings are all proprietary knowledge. And GE is keeping the technology close to the chest, sourcing and manufacturing the materials in-house.
“This is why we’re spending a lot of money to put the plants on the ground and do all the manufacturing ourselves,” Blank said.
The first manufacturing plant for mass production of ceramic matrix composites opened in Asheville, N.C., and there, employees will manufacture the shrouds for the LEAP engine.
Experts from throughout the Cincinnati-Dayton region at GE and local universities are having a hand in researching the material for commercial and military use.
At GE Aviation’s headquarters campus in suburban Cincinnati, it established in 2013 the GE Aviation Research Center in collaboration with the University of Cincinnati Research Institute. The research center includes a new ceramic matrix composite laboratory for low-run production and parts testing. From Evendale, parts and processes head to a GE facility in Delaware that figures out how to scale up the ceramic matrix composite parts to produce thousands of parts at a time.
Also, students and faculty on-site in Evendale and in University of Cincinnati laboratories on-campus are helping GE with inspection technologies.
Whereas decades of experience tell engineers how to inspect metals for cracks, rust and other damages, there’s no history to rely on for inspecting CMCs for problems. That’s where University of Cincinnati contributes.
“We’re looking for defects inside the material and we do that without breaking the material. This is ideal for the development stages of these materials when we want to see how the materials perform under different conditions, also for when the materials enter service for routine inspections,” Simonetti of UC said.
Meanwhile, the University of Dayton Research Institute is helping GE Aviation create and conduct tests for the engines to prove what they’re capable of. Eventually GE tests all new parts on test versions of its jet engines, but before it gets that far, the southwest Ohio company needs to simulate extreme temperatures and other conditions on composite materials to see what works and what doesn’t.
That’s where University of Dayton faculty and staff step in with their expertise on advanced materials. Undergraduate and graduate students also work on GE sponsored projects, according to Jenny Pierce, senior research materials engineer for University of Dayton Research Institute.
“GE is engineering their ceramic matrix composite materials to be able to withstand hotter and hotter temperatures in the turbine engine environment,” Pierce said in written statements.
“Everything gets harder to do and to measure with precision when the test environment is glowing hot. Notably, UDRI is developing in-house capabilities, including methods and apparatus, for testing these materials under relevant thermal and loading conditions well above 2,400 (degrees) Fahrenheit,” she said.
Ceramic matrix composites are different than the related material carbon composites. Ceramic matrix materials can withstand hotter temperatures. GE engines in flight already have fan blades in the cold section of the engine made from carbon composites.
At a basic level, a composite is just a combination of different materials.
“One of the most well-known composites that people don’t know is a composite is concrete,” Blank said.
After filing its first patent on CMC material in 1986, GE is now certifying ceramic matrix composite-made turbine shrouds for the LEAP engine. The LEAP engine is a product of GE’s joint venture with French company Snecma (a division of Safran) called CFM International.
GE Aviation is also testing turbine nozzles and combustor liners made from ceramic matrix composites for a second engine in development, the GE9X, Blank said.
GE Aviation including its West Chester Twp.-based joint venture CFM International employs more than 9,000 people in southwest Ohio. Worldwide, the company employs approximately 44,000 people at more than 80 locations.
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