The growing pressure to increase fuel-efficiency, reduce costs and increase margins, has pushed the aerospace industry to nearly double its use of composites every five years. These advanced materials allow aircraft to shed weight while maintaining the strength required for safe flight.
Composites are generally used in the aerospace industry for many reasons, one of which is to improve lift to weight ratios, therefore improving fuel efficiency and, more importantly, profit margins for airlines.
Three Main Types of Composites in Use Today
There are three main types of aerospace composites: carbon fiber-, glass-, and aramid-reinforced (also known as Kevlar) epoxy. Since 1987, the use of composites in aerospace has doubled every 5 years and the use of composites continues to increase to for both structural applications and components. Fiberglass is the most common composite in use today and first found wide use in the 1950s.
Weight Reduction and Strength
There are many advantages of using composites in the aerospace industry. The most apparent is weight reduction, which is typically in the range of 20-50% over all-metal aircraft. Composites also have a high thermal stability, meaning that they do not expand and contract excessively with large changes in operating temperature. Some composites offer both a high impact resistance and tensile strength as well, which improves both accident survivability and aircraft durability.
Corrosion Resistance and Environmental Benefits
Additionally, being primarily composed of plastics, composites avoid the issue of galvanic corrosion that is caused when two dissimilar metals are put into contact. Composites offer a huge environmental benefit in the form of a much lower load because they are lightweight and increase fuel efficiency, and because their corrosion resistance means that parts last longer. The combination of many of these benefits means that problems caused by the combination of corrosion and fatigue are virtually eliminated with the use of composites in aircraft.
While composites offer a great many advantages, there are a few drawbacks to their use in the aerospace industry. Because composites are a relatively new material, they suffer from high costs as their manufacture is often both labor intensive and complex. Additionally, during service, composites can be dangerous because they are difficult to inspect for flaws and because some composite types can absorb moisture, potentially causing the material to weaken and ultimately fail.
In the future, the pressure for greater fuel efficiency from airlines and environmental activists will continue the push for newer and better composite materials for use in the aerospace industry. This will lead to composites with progressively lighter weights, greater strengths, and greater heat and corrosion resistances. Additionally, the push for greater design simplicity will lead to decreased component counts as composite materials are able to be manufactured with greater and greater complexity in the future.