Carbon Fiber vs Fiberglass: A Comparison of Strength and Applications

Carbon fiber and fiberglass are both composite materials that consist of fibers embedded in a resin matrix. They are widely used in various industries and applications due to their high strength, light weight, and corrosion resistance. However, they also have some significant differences in their properties and performance. In this article, we will compare carbon fiber and fiberglass in terms of their texture, strength, stiffness, weight, thermal expansion, and cost.

Carbon fiber has a smooth and glossy surface that reflects light well. It has a distinctive woven pattern that gives it a high-tech and sleek appearance. Fiberglass, on the other hand, has a rough and dull surface that absorbs light. It has a random or unidirectional fiber orientation that makes it less visually appealing.

Strength is the ability of a material to resist breaking under tension or compression. Carbon fiber is slightly stronger than fiberglass and can replace metals in certain applications. According to Zhongsheng, industrial carbon fiber is more than 20 percent stronger than the best fiberglass. Carbon fiber boasts a strength to weight ratio roughly twice that of fiberglass. Fiberglass, on the other hand, might not have a higher tensile strength but has a dramatically lower tensile modulus. This allows it to bend and take more strain without breaking.

Stiffness is the ability of a material to resist deformation under stress. Carbon fiber is significantly less flexible than fiberglass and is the preferred material for applications in which stiffness and rigidity are essential (mechanical components for example). Carbon fiber’s tensile modulus is 4 times that of fiberglass. For applications in which flexibility is required or rigidity is not imperative, fiberglass is often the preferred choice.

Compared to metals like steel and aluminum, both carbon fiber and fiberglass materials are remarkably light in weight given their inherent strength. In environments and applications in which minimal weight is imperative (aerospace or car racing, for example) both materials are in high demand and used quite frequently. Typically, however, carbon fiber weighs about 15% less than fiberglass composites.

Thermal expansion is the change in size or shape of a material due to temperature changes. Unlike most materials, carbon fiber has a negative coefficient of thermal expansion which means that the material in its purest form actually expands in cold temperatures. However, the matrix in carbon fiber carries a positive coefficient of thermal expansion and the two typically offset one another for an overall coefficient of thermal expansion close to neutral. This means that carbon fiber materials do not contract in cold temperatures while fiberglass products may. So if extreme heat or cold is a factor, and thermal expansion is a concern, carbon fiber may be the better way to go.

Cost is an important factor to consider when choosing between carbon fiber and fiberglass. Generally speaking, carbon fiber is more expensive than fiberglass due to its higher production costs and limited availability. The price of carbon fiber can vary depending on the type, quality, and source of the material. Fiberglass is cheaper and more widely available than carbon fiber, making it more accessible and affordable for many applications.

Carbon fiber and fiberglass are both excellent composite materials that offer high strength, light weight, and corrosion resistance. However, they also have some distinct differences in their texture, strength, stiffness, weight, thermal expansion, and cost. Depending on the specific requirements and preferences of your application, you may choose one over the other or use both in combination. Either way, you can be sure that you are using some of the most advanced and versatile materials available today.