What materials are commonly used as reinforcing components in composite structures?

The use of fiberglass, Aramid fibers, and graphite as reinforcing components in composite structures is well-established in the aviation industry due to their favorable properties.

Fiberglass is widely utilized because it offers good tensile strength and is relatively inexpensive. It is often combined with resin to create a strong but lightweight material ideal for various structural applications in aircraft.

Aramid fibers, such as Kevlar, are known for their exceptional strength-to-weight ratio and impact resistance, making them ideal for applications requiring durability and safety, such as in ballistic protection and aircraft components.

Graphite, or carbon fiber, has gained popularity for its superior strength and stiffness along with a very low weight, making it ideal for high-performance applications in aviation. Carbon fiber composites are often used in airframes and critical structural components to reduce weight while maintaining strength.

These materials collectively provide a combination of strength, weight savings, and resistance to environmental factors, making them suitable for demanding aerospace applications. The other options either include materials that are not typically used for reinforcement in composite structures or do not offer the same effective balance of strength and weight reduction.