CompositesWorld
Issue link: https://cw.epubxp.com/i/697353
CompositesWorld.com 25 NEWS N E W S N S N E W S E N W S W stringer fanges were difcult to melt and adhere to the skin's frst ply. We tested several surface treatments for the stringer fanges, including several types of peel ply." Te peel ply wasn't efective, so ultimately, manual sanding with a fne-grit abrasive was used to prepare the fanges to co-melt with the skin layup. Te ISINTHER project ultimately produced a 600-mm by 800-mm, full-scale demonstrator panel with two, co-consoli- dated straight omega stringers, as well as a cockpit frame stif- ener with shorter stringers. Te fnal parts were molded in a second, modular tool designed to accommodate stringers of diferent sizes and shapes by swapping out interchangeable modules made to a variety of recess sizes and confgurations. Says Rodriguez, "With the modular tool, we can manufacture stifened panels with two types of omegas and even another type of geometry, say a stifener with a joggle. All that needs to be changed would be the stifener modules." FIDAMC has documented its process parameters and conducted extensive testing of the fnal carbon fber/PEEK lami- nates, as correlated with real-time process monitoring. Standard In-plane Shear Strength (IPSS) tests, performed in accordance with ASTM D 3846 methods, were used to assess part degree of consolidation (DOC), and compared to autoclaved samples, because "shear strength is the dominating factor in the matrix- interface performance," says Rodriguez. Te data show that parts have 35-45% crystallinity in the matrix and require no further post-cure nor vacuum bag/autoclave processing. Coupon tests Thermoplastic Composite Wing show complete co-melting and material continuity between skin and stringers. A design allowables database also has been devel- oped. "We've got a mature and robust co-consolidation manufac- turing process, validated through a real aircraft stifened frame, with acceptable porosity," he says. "Te knowledge achieved with those activities will be used in the recently launched Clean Sky 2 OUTCOME project." Anticipating fuselage panels During the previous ISINTHER and Green Regional Aircraft (GRA) projects, FIDAMC produced this cockpit frame using the target technology, shown here ftted inside an aircraft for a test. The OUTCOME project will produce a wing segment as the technology matures, slated to fy on an Airbus aircraft in 2020. Source | FIDAMC Today, fying thermoplastic composite fight-critical parts include the main wing leading edges on the Airbus (Toulouse, France) A380 superjumbo passenger jet and the A340-500/600-series airliners that preceded it, as well as the Gulfstream Aerospace (Savannah, GA, US) G650's rudder and elevators. Aerospace thermoplastic composites application developers include Fokker Aerostructures (Papendrecht, The Netherlands, now part of GKN Aerospace, Redditch, UK) — the key manufacturing partner in the Airbus wing leading edge efort — plus Technocampus (Nantes, France; see Learn More, p. 26), SIDE STORY Thermoplastic composites in fight … for decades Premium Aerotec (Bremen, Germany) and Daher-Socata (Tarbes and Nantes, France), among others. But thermoplastic composite aircraft parts have accrued some history, too: Applications date back to the US military's F-22 jet fghter's landing-gear and weapons-bay doors in the 1980s. And Arnt Ofringa, director of R&D; at Fokker Aerostructures, recalls that in the early 1990s, Fokker developed a thermoplastic composite outer wing trailing edge skin panel or shroud (two per aircraft, left and right) for the Fokker 50 passenger aircraft. The panels were located behind the wing torsion box, in front of the faps and right next to the turboprop engine exhausts (see photo). They were curved parts, 2.15m long by 0.46m wide and made with carbon fber/ polyetherimide (PEI) prepreg supplied by TenCate Advanced Composites BV (Nijverdal, The Netherlands). The panels few on all Fokker 50 aircraft, replacing a more conventional thermoset composite. Says Ofringa, "The epoxy-based composite that was used at frst did not have the temperature resistance needed, right next to the engine exhaust." The Fokker 50's thermoplastic composite outer wing-trailing-edge skin panel replaced an epoxy-based panel that did not have sufcient temperature resistance for its location between turboprop engine exhaust ports and the wing faps. Source | Wings over Europe.com