CompositesWorld, publisher of High-Performance Composites and Composites Technology magazines, as well as the CompositesWorld Weekly e-newsletter, hosted its annual Carbon Fiber conference Dec. 9-12 in Knoxville, Tenn., USA. Attendance was a record this year, with more than 250 people taking in more than 25 presentations. CW was there and has these highlights. Look in the March 2014 issue of High-Performance Composites for a more complete report.
“Emerging Opportunities and Challenges for Carbon Fiber in Passenger Automobiles: Is the CFRP industry ready for mass production?” was the title of Chris Red’s three-hour pre-conference seminar, where attendees listened closely to Red’s predictions of automotive carbon fiber. Red, who heads Composites Forecasts and Consulting LLC (Mesa, Ariz., USA), identified 104 car models that feature OEM-specified carbon fiber composites to some degree, despite his figure of $19.10/lb ($42/kg) material cost for carbon — steel is $0.66/lb ($1.46/kg). In his view: “We can’t get into mid- and high-volume model production scenarios within the next 10 years,” due to high price and processing issues. That said, legislation mandating reductions in greenhouse gas emissions is a powerful driver for OEMs, who must dramatically improve fuel efficiency, as well as end of life recycling goals, over the next 10 years. Red believes that mid- to full-size luxury cars, luxury sports cars and some SUVs and CUVs hold the most promise for carbon composites adoption. The automotive industry today represents about 6 percent of total carbon fiber demand.
Red asserts there are good opportunities for carbon fiber composites in suspension components such as chassis frames, powertrain elements, brakes and wheels, beyond exterior body panels. Of all the OEMs examined, BMW (Munich, Germany) and the Volkswagen Group (Wolfsburg, Germany) are the biggest users of carbon fiber at present. A joint venture between Brembo SpA (Curno, Italy) and SGL Group (Wiesbaden, Germany) is one of the largest single users of carbon fiber materials, and occupy a dominant market share. Not surprisingly, 70 percent of carbon fiber composite part suppliers are located in Europe, the largest including ITCA Colonnella SpA (Colonnella, Italy), Sotira (Meslay du Maine, France) and Mubea Carbo Tech Composites GmbH (Salzburg, Germany). Some North American firms made his “biggest” composites supplier list, including Morrison Molded Fiberglass Co. (Ashtabula, Ohio), Multimatic Inc. (Markham, Ontario, Canada) and Plasan Carbon Composites (Bennington, Vermont and Walker, Mich.). Red concluded that, despite a drop in carbon fiber usage in automotive of nearly 50 percent between 2005 and 2010, over the next 10 years, without a speculative demand add-on, the identified vehicle population is expected to consume more than 173 million lbs/78.6 million kgs of carbon fiber. “Outside of wind energy, the automobile represents the biggest growth opportunity for carbon fiber market growth and penetration,” he says.
While difficult to single out specific presentations, given the quality of speakers and topics, several standouts included interesting applications under development or entering production. Gary Roberts, a research materials engineer with NASA Glenn Research Center (Cleveland, Ohio, USA), discussed work being done in collaboration with A&P Technology (Cincinnati, Ohio, USA), Drexel University and the Army Research Laboratory (ARL, Adelphi, Md., USA) on a hybrid composite/metal gear concept for rotorcraft drive systems. A helicopter’s drive system constitutes up to 15 percent of the craft’s empty dry weight, and OEMs and operators have long wished for ways to reduce system weight. Using composites with steel, points out Roberts, shifts the gear dynamics to a higher frequency, which could help control vibration and noise at critical frequencies. Replacing the central web of a small, round toothed steel “spur” gear with carbon composite, in a sandwich design that maintained the outer steel teeth and inner steel hub, brought a 20 percent weight reduction, with no damage or degradation during a stringent endurance test. While static testing showed some slight delaminations at loads far beyond any design loads, there was no crushing of the composite material, despite myriad loads that include radial, torque and vibration. Roberts says the team is scaling up to full size helical bull gear, and looking at ways to emulate the dynamic loads at realistic hot oil temperatures and strains. Three major U.S. OEMs are reportedly interested in the research results.
Dave Kehrl, senior project engineer at A&P Technology described his company’s support of The Boeing Co.’s (Chicago, Ill., USA) 787 Dreamliner program, believed by CompositesWorld to be the first public disclosure of this work. Starting in 2003, during initial trade studies, Boeing initially thought that fuselage frames would be titanium, according to Kehrl, but when composites were ultimately chosen, a different solution was needed — one that could conform to the curved fuselage shape. A&P developed a braid architecture, and equipment, that could align the central, axial fibers with the tangent of the curvature; varying part curvature was defined by the braiding mandrels, to form overbraided, multi-ply curved preforms that met the many load cases at each skin/stringer/frame intersection, defined by the finite element model. According to Kehrl, it was the first braided and resin infused primary structure for aircraft. Begun in 2005, production is now ramping up to meet the 787’s production schedule. Infusion is done by C&D Zodiac (Huntington Beach, Calif., USA) in North America, and by Alenia Aermacchi (Venegono Superiori, Italy) in Europe.
The wind industry has long been forecast as major consumer of carbon fiber, particularly in wind blade spar caps. Even projections offered at the Carbon Fiber conference reported aerospace and wind as the two largest markets for the material now and for several years to come. However, two presentations at the conference cast carbon fiber's future in wind in doubt. Steve Johnson, manufacturing engineering manager at GE Wind Energy, was overall positive about wind's future in North America — wind, at $0.06/kWhr is competitive with natural gas — but noted that remaining competitive requires that manufacturing costs be kept in check. "Cost is king in the wind industry," he said. In addition, although low blade weight is important, it's not critical, thus carbon fiber is not considered, by GE, to be an essential manufacturing material, particularly given carbon fiber's relatively high cost. A carbon fiber spar cap, Johnson said, weighs 80 percent less than a glass fiber spar cap, but costs five times more. "We love carbon fiber, but we hate the cost associated with it," he concluded.
Johnson was followed by Aaron Barr, technical advisor at MAKE Consulting (Chicago, Ill., USA), who also addressed carbon fiber use in wind blades. Like Johnson, Barr is optimistic about global wind energy production — 2013 will be a "down" year, followed by several years of anticipated expansion. Barr noted that only two blade manufacturers, Vestas and Gamesa, are using carbon fiber in spar caps, with Vestas accounting for a vast majority of that total. Vestas, however, is struggling financially and faces an uncertain future. Barr noted that carbon fiber's penetration as a percentage of installed wind blades is expected to drop from a high of 23 percent in 2012 to 19 percent in 2013 to 18 percent by 2016. "There's no magic number for when you need carbon fiber," he said, and projects "flat" carbon fiber use in wind blades through 2020. "All of this, however," he said, "is underpinned by just a few OEMs using carbon fiber." The tipping point for carbon fiber might come in the form of a cheaper precursor, which would be expected to reduce the cost of carbon fiber to $5/lb, which MAKE anticipates will occur by 2018.
An example of how elegant and simple a composites solution can be was described by Mark Campbell, new product development, of MW Industries Inc.’s (Rosemont, Ill., USA) Hyperco division, the world’s largest supplier of suspension components and springs to the racing industry. He related that, despite his position as leader of new product development, company management made the decision to explore carbon fiber composites for racing springs. Initial helical designs were complete failures, with insufficient strength in torsion. As the company looked at other ways to use carbon, including “bump stops” on NASCAR race cars (which were ultimately banned by NASCAR racing officials), an “a-ha” moment resulted when several thin “Belleville washers” or carbon/epoxy discs were stacked atop each other. By molding in lip/flange details, the discs interlock when stacked, and can be flipped over and restacked for different spring rates. Hyperco is able to achieve very high spring rates when the discs are compressed, without any internal side loading friction on the spring shaft that is typical of conventional coil springs, because the discs remain parallel in compression. A&P Technology supplied the materials and TCR Composites Inc. (Ogden, Utah) supplied prepreg. The revolutionary spring design, which Campbell says is “game-changing,” is termed Carbon Composite Bellow Springs by the company, and is revolutionizing the sports car racing industry. Other sporting goods applications are on the horizon, says Campbell.
Many eyebrows were raised at the conference by Patrick Blanchard, technical leader, Composites Group at Ford Motor Co. Research & Advanced Engineering, who addressed emerging CAFE standards and lightweighting efforts at the carmaker. He reminded the audience that CAFE targets progress annually and require 3.5 percent fuel efficiency improvements year over year through 2025. He also noted that Ford research shows that consumers are not concerned about vehicle weight. They are most concerned with vehicle handling, braking and safety, and although vehicle weight affects these things, weight by itself is not important. Finally, he reported that powertrain advances involving hybrid and electric technologies will allow a company like Ford to meet CAFE targets; reducing vehicle weight will extend the range of high-efficiency cars, but weight elimination is not necessary to increase efficiency. That said, weight is an issue. New customer features in cars and trucks, since 1998, have added 17 lb/year to each new car model and 43 lb/year to each new truck model. Ford, Blanchard noted, is looking at aluminum and lightweight steel to help trim mass. These "legacy" materials fit best with Ford's manufacturing systems, which of course favor metals. Carbon fiber, he noted, needs to meet these requirements: be scalable, improve design and CAE tools, develop robust repair technologies, prove adequate supply, and prove compatibility with vehicle painting processes. Blanchard did not mention carbon fiber price as a hurdle, but in question and answer following his presentation he said that he left price out of his presenation because Ford infrasctructure requirements present bigger hurdles to the material. Blanchard said 39 assembly plants globally, producing 7 million vehicles a year. Reconfiguring those plants to accommodate carbon fiber manufacture would be prohibitively expensive. Blanchard did say that he thinks composites use in automotive has a future, particularly in multimaterial applications, but made clear that carbon fiber use at Ford is not a forgone conclusion.