The composite structure involved in all contents generally refers to the carbon fiber prepreg ply structure.

Strength and stiffness

Since it is a structural component, the designer should first consider strength and stiffness. Under the action of external force load, components have the ability to resist deformation and failure, but this ability is limited.

How to determine the service load of components without exceeding the capacity limit of components is calculated by material mechanics. The capacity limit of the component is the problem that the designer of carbon fiber composite structure needs to consider.

By reasonably matching fiber and resin, optimizing fiber layout and using the least materials to meet the design needs, it reflects the exquisite skills of composite designers. However, the factors that determine the strength and stiffness of composites are not only related to the types of fibers and resins, but also related to the laying direction of carbon fibers and the combination between layers.

Therefore, when designing carbon fiber composite structural components, designers need to consider the mechanical properties of three levels of structure.

The mechanical properties of single-layer materials composed of matrix and reinforcement depend on the mechanical properties of component materials, phase geometry (shape, distribution and content of each phase) and the properties of interface area.

The mechanical properties of a laminate composed of single-layer materials depend on the mechanical properties of the single-layer materials and the laying geometry (thickness, laying direction and laying sequence of each single layer).

The topmost structure refers to the engineering structure or product structure, and its mechanical properties depend on the mechanical properties and structural geometry of the laminate.

stability

In addition to the strength and stiffness requirements, the designer also needs to consider the instability of composite components, especially for some slender rod structures, which should be able to ensure their original linear equilibrium state under pressure. For some frame structural components, warpage and instability will also occur if the paving is uneven, so pay special attention in the manufacturing process. It is better to use symmetrical paving to prevent uneven deformation.

Generally, instability is not allowed when the component does not reach the limit load. However, if instability can occur for some special requirements, it should be considered that the instability process will not affect the ultimate load in the design process.