Fiber composites, also known as composites, consist of two main components: reinforcing fibers and a supporting matrix. The fibres provide the necessary strength, while the matrix stabilizes the fibres and brings out their properties. The interaction of these components creates materials that have far better mechanical and physical properties than their individual parts.
This makes fiber composites ideal for applications that require lightweight construction, strength and durability. The structure of a fiber composite, including fiber angle, volume fraction and layer order, can be adjusted depending on the application to ensure optimal performance.
Three main fiber types are used for technical fiber composites:
These fibers are often processed in the form of continuous fibers and formed into fabrics, braids or mats to facilitate handling in the production of composite materials.
The matrix in a fiber composite holds the fibers together and transfers the loads to the fibers. There are two main types of matrix materials:
The choice of matrix depends on the requirements for strength, processing and the final application.
Carbon fibers are obtained from carbon-containing material in a complex industrial process. They are characterized by their high strength, rigidity and low elongation at break. Carbon fiber composites are extremely dimensionally stable, even when exposed to temperature changes, and have a low to negative coefficient of thermal expansion. This means that they retain their shape even at high temperatures. In addition, carbon fibers are electrically and thermally conductive, non-magnetic and X-ray transparent, which makes them ideal for high-tech applications such as in aerospace, medical technology and automotive engineering.
Glass fibers are the most commonly used reinforcing fibers worldwide, mainly due to their favorable price-performance ratio. They offer good mechanical properties and are chemically resistant. Glass fibers are often used in the electronics industry for printed circuit boards (PCB) and are known for their dielectric properties. Depending on the requirements, different types of glass fibers can be used to achieve higher mechanical strength or temperature resistance. Composite materials made of glass fiber are often referred to as GRP (glass fiber reinforced plastic).
Aramid fibers have unique properties that make them particularly suitable for applications that require high dimensional stability. They have a negative coefficient of thermal expansion, which means that they shrink when heated. This property enables the production of extremely precise components. Aramid fibers also offer higher impact strength than carbon fibers and are particularly suitable when high energy absorption is required, for example in protective clothing or safety-critical components. However, their specific strength and modulus of elasticity are somewhat lower than those of carbon fibers. Aramid composites are often referred to as AFK (aramid fiber reinforced plastic).