DragonPlate has compiled a glossary of carbon fiber terms to help you understand the content that we have provided about carbon fiber materials on the website.
3-Point Bending: A condition where both ends of a beam are supported and a load is applied at the mid-span.
Brittle Material: A material that does not yield, but instead fails suddenly when the ultimate stress is exceeded.
Carbon Fiber: A high strength, high stiffness material that when combined with a resin matrix creates a composite with exceptional mechanical properties.
CFRP: Abbreviated form of carbon-fiber reinforced plastic
Composite Sandwich Core: In a composite sandwich structure, the core is a lower density material placed close to the neutral axis in order to increase the stiffness to weight ratio.
Composite material: A material created by combining two or more materials such that the final construction exploits certain properties from each. In the construction of carbon-fiber reinforced plastics, the high strength, high stiffness of the carbon fibers are combined with a low density stable matrix to create a combined material with desirable material properties.
Epoxy: A polymer resin that hardens when combined with a catalyst. Epoxy is one of the most common materials used to form the matrix in carbon-fiber fabrication.
Fiberglass: A glass fiber reinforced plastic similar to carbon-fiber, but with much lower strength and stiffness, but also much lower cost.
Homogeneous: Defined as having a uniform composition throughout the material.
Isotropic: Defined as having the same properties (mechanical, electrical, thermal, etc) in all directions. Carbon-Fiber laminates are typically highly directional, having high stiffness and strength only along the longitudinal directions of the fibers.
Matrix: In a composite material the matrix comprises the stable "fill" which holds the fiber reinforcement. By itself the matrix is typically much weaker than the fibers, particularly in tension. The matrix's primary function is to transfer the loads between the fibers within the composite material.
Modulus of Elasticity: A measure of the stiffness of a material, defined as the axial stress divided by the axial strain. The higher the modulus, the stiffer the material (i.e. the greater the stress necessary to cause deformation). Also known as Young's Modulus.
Poisson's Ratio: When a material is stretched due to an applied load, it elongates in the axial direction and contracts in the perpendicular, or transverse, direction. The poisson's ratio is defined as the axial strain divided by the transverse strain.
Quasi-Isotropic: In a composite material, the placement of individual laminates, or plies, so that the fibers are directed along multiple directions. The result is a material with approximate isotropy in mechanical properties.
Polyacrylonitrile (PAN): A raw material commonly used to make carbon-fiber.
Pultrusion: A process which creates an extremely stiff rod, tube, or other cross-section whereby all of the carbon fibers are aligned along the longitudinal axis.
Reinforced carbon-carbon (RCC): Carbon-reinforced graphite composite used in high temperature applications.
Shear Modulus: Defined as the shear stress divided by the shear strain. Also known as the Modulus of Rigidity.
Shear Stress: The component of stress parallel to the cross-sectional face of a material.
Shear Strain: Deformation of a material caused by a shear stress. A shear strain causes skewing of a material element.
Strain: The deformation of a material caused by an applied load. The strain is defined as the change in length divided by the original length of a material.
Stress: Defined as the force per unit area. The stresses within a composite are a function of the material properties of the materials, the geometry, and the loading condition.
Ultimate Tensile Strength: The maximum stress a material can withstand in tension, above which failure will occur.
Veneer: A thin, highly flexible sheet of carbon-fiber.
Yield Strength: The stress above which a material with remain permanently deformed even when the applied load is removed.