The Understanding of Carbon Fiber Modulus

Are you troubled by carbon fiber materials’ lack of rigidity when trying to increase the stiffness and strength of car body frame structures and sports equipment performance? The modulus of carbon fiber is the key to these limitations.

This guide will take you to an in-depth analysis of its definition, modulus grade, influencing factors, applications, etc., to provide a reference for your material selection. Help you create products with higher performance.

1. What is Modulus(Modulus of Elasticity)?

Modulus, usually called elastic modulus or Young’s modulus. It refers to the ability of a material to resist elastic deformation during the elastic deformation stage and is the ratio of stress to strain. It is an indicator of material stiffness, with units of GPa or MSI.

Elastic modulus is generally used to measure the stiffness of a material, while tensile strength reflects the ability of a material to resist fracture under stress

2. Modulus Grades of Carbon Fiber

Carbon fiber is generally divided into the following grades according to the amount of the modulus:

• Standard Modulus: It is the most common and widely used type of carbon fiber, ranging from 33-35 MSI
• Medium Modulus: Its modulus and strength are slightly higher, and generally range from 42-47MSI
• High Modulus: It has undergone a continuous high-temperature carbonization process of more than 2000℃ and has relatively high stiffness, generally ranging from 55-60MSI.
• Ultra-high modulus: It requires ultra-high temperature heat treatment of 3000-3500℃, so the cost is extremely high. It is very brittle and has an extremely low deformation rate. It is mainly used in aerospace, with a modulus of 110-135 MSI,

3. Factors Affecting the Carbon Fiber Modulus

Many factors affect the modulus of carbon fiber: 

• Precursor type: 

Carbon fiber precursors generally include Pan, petroleum asphalt, viscose fiber, etc. Pan is the most widely used raw material for manufacturing standard modulus carbon fiber. Asphalt carbon fiber with asphalt as raw material has characteristics such as high modulus and high thermal conductivity.

• Preparation process：

Carbon fiber manufacturing requires processes from raw silk preparation to pre-oxidation stabilization treatment, high-temperature carbonization, graphitization treatment, surface treatment, and sizing. As the production process becomes more in-depth, the required temperature continues to rise, which will cause the modulus of carbon fiber to change continuously.

• Fiber orientation：

Carbon fiber modulus in the fiber direction is very high, but very low in the transverse direction, which causes the carbon fiber material to be anisotropic. Therefore, when manufacturing carbon fiber composite materials or components, changing the fiber laying direction can change its modulus.

• Resin matrix type：

As the matrix of carbon fiber composites, resin determines the composites’ mechanical properties. For example, the epoxy resin modulus is low, which limits the stiffness of the composite in the vertical direction. PEEK and polyimide have a higher modulus and are generally used as the matrix for producing high-modulus composites.

4. Application of Carbon Fiber Modulus

• Aerospace:

High-modulus composite carbon fiber reinforced materials are generally used in aircraft fuselages, drone frames, and satellite frame structures. Its superior rigidity, dimensional stability, and lightweight can save fuel and increase load capacity.

• Automobile Manufacture：

Medium modulus composite carbon fiber materials are used in body frames, chassis structures, and brake systems. Its lightweight, high-strength, and high-rigidity cars can improve fuel efficiency and ensure safety performance.

• Outdoor sports equipment：

Standard modulus carbon fiber material is for lower cost and wider application. It’s generally used to manufacture high-performance bicycle frames, golf clubs, pickleball rackets, paddles, and other sports equipment. It can increase your products’ service life, and improve cost-effectiveness and equipment performance with good rigidity.

• Precise instrument

Ultra-high modulus carbon fiber composite material has superior stiffness, strength, and thermal properties. As a result, it can be used in optical instrument mounts, measuring devices, and stands where data accuracy is required. To ensure very low deformation rates and accurate data measurement.

5. The Challenge and Solution

Challenge 1: The Cost of High-modulus Carbon Fiber Materials is High

We all know that the higher the modulus of carbon fiber materials, the more complex the manufacturing process, the higher the energy consumption, and the higher the cost.

Solution：

Introduce advanced equipment, improve manufacturing techniques and processes, and scale up and mass-produce the production performance of carbon fiber materials.

Challenge 2: Anisotropy Resulting in Uneven Performance

The properties difference of carbon fiber between the transverse and longitudinal leads to its anisotropy, which limits its wide application.

Solution：

Optimize the layup design, using the way of multilayer and cross layup. It can performance defects due to equilibrium anisotropy.

Challenge 3: Brittleness Problem

The higher the modulus of carbon fiber, the higher its stiffness and the greater its brittleness, which limits its application.

Solution：

It has high strength and rigidity in the lateral direction, but it’s also very easy to break and delaminate under stress. Therefore, when manufacturing composite carbon fiber materials, the ply design is optimized, and cross and multi-angle ply methods are used to improve its brittleness and increase toughness.

Challenge 4: Modulus and Strength Balance。

As the modulus of carbon fiber increases, the strength of the material does not necessarily increase.

Solution：

We can select the right carbon fiber type and resin matrix for your particular application.

6. Conclusion

Before choosing the right carbon fiber material, you need to have a profound understanding of carbon fiber modulus. It can help you accurately balance mechanical and thermal properties in the design. This will improve your product performance and extend its service life, gaining an advantage in market competition.

If you have any questions, we are always ready to provide you with professional solution design and data support!