Carbon Fiber is Anisotropic – Here’s Why That’s Awesome

Many amazing advancements in carbon fiber composites are because carbon fiber is anisotropic. That is, the carbon fiber properties depend on the orientation of the fibers. This directionality means that we can build wrapped carbon tubes to have customized attributes such as hoop strength and deflection. 

Isotropy 

Isotropic materials have identical material properties in all directions at any given point. When we apply force to an isotropic material at any point along the x, y, or z axis, the material will exhibit the same stress, hardness, elasticity, and strength. The term comes from the Greek isos (equal), and tropos (way). Isotropic materials are highly predictable because the properties of its molecules behave the same in all directions. Isotropic materials, like glass, plastic, and metal, are highly formable and can take any shape.

Anisotropy

When the properties of a material vary with orientation, that material is anisotropic. In carbon fiber, the individual carbon atoms are linked together with a crystalline structure oriented along the direction of the fibers. The atoms slip over one another or distort in relation to one another more easily in some directions than others. This directionality of properties is what makes carbon fiber anisotropic.  

Carbon fiber composites take advantage of anisotropy by orienting fibers to achieve certain attributes. We rely on the directionality of carbon fiber’s properties every time we design a wrapped carbon tube; these tubes begin as layers of carbon fiber fabric and each layer can have the fibers oriented differently from the next.

Controlling the fiber orientation in the layup allows us to design the tube to exhibit different performance attributes, such as flexibility, impact resistance, and hoop strength. 

Twill weave carbon fiber fabric approximates isotropy and makes it possible to create three dimensional shapes with carbon fiber fabric. Unidirectional carbon fiber fabric (in which all fibers are lined up in the same direction) does not easily bend and form to three dimensional shapes.  

Choose Goodwinds Composites for Your Carbon Composites 

Goodwinds Composites engineers possess vast experience and expertise at designing composite rods and tubes to be effective components for your application. We understand how to engineer the precise properties you desire from your structural composite reinforcements. Contact us to get a quote or learn more about our services.