The aviation industry generates about 2% of all human-induced Co2 emissions and 12% of the emissions of the transportation industry. On 6 March 2017, the 36-State ICAO Council has adopted a new aircraft CO2 emissions standard which shall reduce the impact of aviation greenhouse gas emissions on the global climate by mandating an increase in efficiency for new aircraft. It will on an average require a 4% reduction in the cruise fuel consumption of new aircraft starting in 2028 as compared to 2015.
Low fuel efficiency hits airlines with a double whammy. First, the higher consumption of fuel leads to larger emissions of greenhouse gases and contributes to global warming. Second, higher fuel consumption leads to a higher cost which is already the highest component of the operational cost of airlines. Aircraft OEMs have forever been on the quest to increase their fuel efficiency. Now it is the law as well as the competitive industry which mandates such improvements.
For a given payload, lower airframe weight leads to lower drag which in turn increases the fuel efficiency. A reduction in airframe weight of 100 kg can result in lower fuel consumption to the tune of 19,000 litres in a year. Thus, weight reduction is a win-win for airlines and the environment.
Lightweighting: In its quest for lighter, yet stronger materials the industry has come a long way from the use of Aluminium, Steel & Titanium to the use of composites, which have increased in proportion from a mere 4% in the 1970s to around 50% of the structural weight today. As demonstrated by next-generation aircraft, B787, attaining 20% higher fuel efficiency, 5% more reduction in noise, and 30% lower maintenance cost than B767. The use of composites made this feat possible, and it opens the door of possibilities for adaptation of thermoplastic composites as well.
For long thermoset plastics have been the mainstay of the aviation industry. They were most certainly an improvement over metals. But the industry might be on the cusp; metallic parts and thermoset composite parts, are being replaced (though in smaller proportions) with their lighter weight brethren, the thermoplastic composites in the aerospace industry.
Turning a new leaf: A Better material & strong growth fundamentals
Though thermoplastic composite’s applications are very common in the automotive industry, their share is minuscule in the aerospace industry. Currently, thermoset composites dominate the aerospace composites market because of their low cost & high quality. But they are not without shortcomings; lack of reusability, longer processing time & processing costs are their major lacunas.
The newly developed thermoplastic composites are blessed with lower weight, an indefinite shelf life, low moisture absorption, excellent thermal stability and chemical resistance, high toughness and damage tolerance, solvent resistance and low dielectric constant. Armed with such qualities thermoplastic composites are set to change the aerospace industry.
Competitive Edge: Thermoplastic composites tower over thermoset composites with many qualities. They are better in terms of processing, material properties, cycle time, and life cycle cost.
Processing Superiority: Reduction in cycle time i.e. faster curing and production ranging from one-fifth to a third reduction in processing time, low-cost fabrication & easy processing. Also, there are avenues for increased automation.
Material Superiority: Lightweight structure, lower part count as they can even be welded, enabling fabrication of larger components without adhesive bonding, and riveting, thus reducing the number of components involved. Lower VOC emissions is an added advantage.
Galvanic corrosion between dissimilar materials is one of the prime causes of structural failures. With thermoplastics in place, the possibility of galvanic corrosion is ruled out as components can be fused together making the aircraft safer.
The Cost Advantage: The reusability of parts and scraps is a major advantage and shall reduce the overall cost of parts substantially. Lower energy requirement while processing it is also a cost advantage. As of now thermoplastic composites used in aerospace are expensive, but the life cycle cost advantages are inherent. In toto, thermoplastic composite’s reusability, excellent properties and lightweight structure are destined to save millions for airlines.
Unsurprisingly thermoplastic composites are fast becoming the blue-eyed boy of the aerospace industry. There has been a surge in the use of thermoplastic composites in the last 10 years. Radical improvement in their properties has won over the initial scepticism regarding their inferior properties. Today they are used in both airframes and interior of aircraft. Some of the applications are clips, cleats, fixed-wing leading edges, J-nose leading edges, panels for fuselage, profiles & brackets, ribs & angle brackets, control surface parts, seat backs, window panels, and cockpit floor.
There seems to exist a reasonable scope for thermoplastics to grab a sizeable portion of aircraft components, provided that they address the issue of very high costs, and undergo improvement in properties.
Stratview Research, after analysing a plethora of factors, expects the market to reach over $630 mn mark by 2023, galloping at a CAGR of near double digits. The growth till 2023 is prognosticated on various fundamental factors.
The Growth Hotspots
Commercial aircraft dominate the market with over 3/4th share. Stratview Research foretells the growth to march on at around double-digit CAGR. Europe is projected to remain the largest thermoplastic composites market for the commercial aircraft segment over the next five years, driven by increasing production rates of A350XWB coupled with high thermoplastic composites content per aircraft. USA is expected to remain the largest thermoplastic composites market, driven by B787 of Boeing and G500, G550, G600, and G650 of Gulfstream Aerospace aircraft programs. Germany and France are also expected to report double-digit growth.
The nitty-gritty of thermoplastic composite's application
Thermoplastic composites in the aerospace industry are used in the form of laminates, uni-directional tape, and fabric prepreg. PPS, PEEK, PEKK, and PEI are the major thermoplastic resins used with either glass fiber or carbon fiber or aramid fiber to manufacture composite parts. So far, thermoplastic composites are used mainly used in Interiors and Airframe. Airframe dominates the market by over half of the share and is poised to retain the lead with a high CAGR. Clips and cleats are the most prominent applications which are made from carbon fibers with either PPS or PEEK resins. There are reports that Boeing’s B787 family requires between 10,000 and 15,000 such composite parts per aircraft, while the Airbus A350 XWB is believed to use around 8,000 per aircraft.
In terms of fiber, carbon fibers have the major market share. All the major applications of thermoplastic composites in the aerospace industry are made with carbon fibers. Carbon fiber offers numerous advantages, such as excellent weight reduction, high strength-to-weight ratio, high tensile and compressive strength, low coefficient of thermal expansion, and high fatigue resistance, but at a very high cost. Glass fibers, which however lag in mechanical performance, outperform carbon fibers in the economy. Glass fibers are roughly 15 to 20 times less expensive when compared with carbon fibers. This has been the major driving force for glass fibers in marking its presence in those areas where high performance is not the biggest concern. Currently, the largest component in terms of part geometry is believed to be A380’s J nose which is made up of glass fibers impregnated with PPS resins.
A transforming market
The global aerospace thermoplastic composites market is highly consolidated with the presence of less than 25 active players. The top 5 players, GKN Aerospace, Premium Aerotec, Daher, Dutch Thermoplastic Components, and Avanco Group (Xperion Performance Polymer Composite captured around nine-tenths of the market in 2017.
The market is abuzz with new product developments, merger-acquisitions, joint ventures. In 2018, Bucher Leichtbau and Ensinger developed thermoplastic connector mountings for aircraft interiors. In 2017, Daher designed and developed the first-ever thermoplastic composite wing rib for a commercial aircraft, which slashes the component weight by 35% vis-a-vis Aluminium.
In 2017, Liberty Hall Capital Partners, a private equity firm, acquired Quatro Composites, L.L.C. a leading supplier of thermoplastic composites, which is integrated into AIM Aerospace Corp.
Avanco Group (Xperion Performance Polymer Composites) has also formed a joint venture with Cutting Dynamics Inc. (CDI) for thermoplastic composites in 2017.
A glimpse of the Future
With weight and emission reduction being an exigent matter, the future of lightweight thermoplastic composites looks bright. From the vantage point of strong global demand for aircraft, increasing penetration of thermoplastic composite, and ICAO guidelines almost mandating the improvements in efficiency; the growth potential is large.
The relative advantage over thermoset composites in terms of faster & low-cost production is just in time to meet the challenges of faster production. The increased production rates, deliveries, big order book and larger backlogs of major airlines are going to assure high future growth.
The future of thermoplastics hinges on the progress on the fronts of cost reduction, better and properties to suit newer applications. Because of its reusability, over-all cost reduction will not be as herculean a task. With advancement in technology, one can be sanguine of a future with better thermoplastic composites.