Carbon fiber reinforcement is usually required when:

 Structural Reinforcement: 

When a structure (such as a building, bridge or other infrastructure) experiences fatigue, aging, cracks or other damage, carbon fiber reinforcement can be used to increase the structure's strength and stiffness. Carbon fiber reinforcement can reduce the load on the structure, extend its service life and prevent further damage.

 High strength requirements: 

Certain application fields require materials with extremely high strength and stiffness, such as aerospace, automobiles, sports equipment, etc. Carbon fiber is a lightweight but extremely strong material, so it is often used in structural reinforcement and component manufacturing in these areas.

 Weight Limitations:

 Carbon fiber has a very low density and is much lighter than traditional metal materials. In some applications where weight reduction is required, such as aerospace, automotive and sports equipment manufacturing, the use of carbon fiber can achieve significant weight savings, improve performance and fuel efficiency.

 Corrosion resistance requirements: 

Carbon fiber has good corrosion resistance and high resistance to most chemicals. Therefore, in some environments that need to prevent corrosion, such as marine, chemical and other fields, carbon fiber reinforcement can provide longer service life and better durability.

Although carbon fiber reinforcements are an effective solution in many situations, they are not required in all situations. The following are examples of situations where carbon fiber reinforcement may not be required:

 1. Low Load Applications: If the structure or component is in a low load environment and does not require additional strength or stiffness reinforcement, then the use of carbon fiber reinforcement may not be necessary. In this case, it may be more appropriate to use other more economical and suitable materials.

 2. Special Requirements: Some special requirements may not be met through the use of carbon fiber reinforcement. For example, if specific electrical conductivity, magnetism, insulation, or other special properties are required, other materials or methods may need to be selected.