Design and Analysis of Composite Structures for Automotive Applications

Appendix AMechanical Properties of Composites

A.1 Fibers

A.1.1 Glass Fibers

Glass fiber was the first kind of fiber that was widely used as a reinforcement fiber. The so‐called E‐glass, with over 90% of all glass fibers used for reinforced plastics has the greatest share. Glass fiber has an isotropic behavior. The modulus of elasticity is approximately 70 GPa, as large as that of aluminum and about a third of the modulus of elasticity for steel. The tensile strength is nearly 2.4 GPa and clearly below that of carbon fibers. This value is definitely higher than the strengths of aluminum and most steel alloys. The density of glass fibers is roughly 2600 kg m⁻³.

A.1.2 Carbon Fibers

Carbon fibers are currently the most widely spread reinforcement fibers for high quality parts. The density of carbon fibers is a relatively low 1600–2000 kg m⁻³. Carbon fibers are highly anisotropic, like aramid fibers. The thermal expansion coefficient is also negative as it is for aramid fibers. The carbon fibers possess a high fatigue endurance limit. The dynamic characteristics of laminates based on carbon fibers for reinforcement dominate the dynamic characteristics of such materials as steel or aluminum. These fibers possess exceptional chemical and thermal properties and good resistance to corrosion. Strength, stiffness and thermal conductivity substantially differ depending on the type of fiber.

A.1.3 Aramid Fibers

Aramid fibers are characterized by the high‐strength, low density, high impact ...