What happens when you hold a flame just a couple inches under a strip of thermoplastic? Attendees at the standing-room only CAMX pre-conference tutorial on thermoplastics composites found out first hand. Speaker Arnt Offringa, director of research and development at Fokker Aerostructures, handed out the strips and lighters, and people conducted the mini-experiment. After 10 to 15 seconds, you could bend the thermoplastic into a V-shape.
Though rudimentary, the hands-on activity displayed one of the benefits of thermoplastic composites: They can be reheated above their melting temperature for additional processing. Fokker Aerostructures manufactures lightweight structures, modules and landing gear for the aerospace and defense industry. Using thermoplastics for many of the components brings customers two highly sought after benefits: It lowers the weight of the aircraft and reduces costs.
Some other attractive characteristics of thermoplastics include:
- Unlimited storage and layup at ambient conditions in normal factory conditions
- High material toughness
- Excellent fire, smoke and toxicity properties
Thermoplastics are a relatively young technology, said Offringa. But they’re making headway in the aerospace industry. Offringa cited the Gulfstream G650 as an example. The rudder and two elevators on the twin-engine business jet airplane were originally constructed of aluminum, then later composites. A few years ago, Fokker Aerostructures began making the parts from thermoplastics. The G650 rudder and elevators require high torsional stiffness and little bending stiffness. They are designed to allow buckling at 70 percent limit load, which provides a weight advantage over a honeycomb sandwich design. The transition to thermoplastic composites for these applications yielded a 10 percent reduction in weight and 20 percent cost savings.
Offringa then summarized production technologies for thermoplastic composites, including thermofolding, press forming, welding and co-consolidation. He also discussed how the technologies are moving into the automotive arena as the industry strives to lower carbon dioxide emissions and reduce weight through new materials. Automakers also seek recyclable and affordable options, which thermoplastics can provide. Lower-cost matrices, including polypropylene and polyamide, are well suited to automotive applications.