What is the fundamental reason for the difference in the strength of carbon fiber panels?

Similar to carbon fiber cloth, carbon fiber board belongs to carbon fiber composite material, which is a new type of high-strength reinforcement material. Carbon fiber board is a carbon fiber board formed by infiltrating and hardening carbon fibers arranged in the same direction with resin.

In the technical specification for the safety appraisal of engineering structural reinforcement materials, it is also high-strength class I, and the tensile strength of the carbon plate is required to be ≥2400MPa, which is lower than the tensile strength of carbon fiber cloth ≥3400MPa. Although the carbon plate has undergone explosive damage, the strength It can only reach 3000-32000MPa; on the other hand, the main materials of carbon plate and carbon fiber cloth are carbon fiber strands. Now carbon fiber strands can even reach more than 5000Mpa. Why is the strength of the composite carbon fiber plate so poor?

On this issue, but also from the perspective of material composition. The carbon fiber board is extruded from carbon fiber strands and epoxy resin. The addition of epoxy resin reduces the content of carbon fiber strands in disguised form. In the process that the carbon fiber board and the base material form an overall joint force, the carbon fiber precursor is mainly subjected to tensile stress. In order to ensure the strength of the carbon fiber sheet, the content of the carbon fiber precursor becomes a necessary guarantee. If the volume fraction of the precursor fiber in the carbon fiber sheet is too low, the strength of the carbon fiber sheet is bound to be insufficient.

Although carbon fiber board is not as strong as carbon fiber cloth, in fact, the reinforcement effect of one carbon fiber board is equivalent to 4-8 pieces of carbon cloth. When we use carbon fiber plates for reinforcement, we cannot determine only by strength, but should choose according to actual needs. In addition, in the carbon fiber board, the carbon fiber filament and the internal epoxy resin belong to the composite section. How to make the two form a better composite section and improve the joint force of the two is also a problem that needs to be solved in the high-strength carbon fiber board.