how to reduce the weight of composite structures？

When machining a part with composite materials, a question often arises, can it be made lighter? The answer is, of course, yes, but the approach to weight reduction for composite parts is not always fixed. For composite parts, there needs to be a balance between cost and performance.

Before a composite design or component can be optimized, the component must be fully studied. Even replacing fiberglass parts with higher performance materials such as carbon fiber requires some knowledge to simply make parts lighter. Several of the current major methods of reducing composite parts include:

1. Optimize the ratio of resin to reinforcing fiber

To maximize the design capabilities of existing composite parts, the ratio of resin to reinforcing fibers can be optimized. In wet layup, too little resin can result in insufficient impregnation of the fibers, resulting in improper load distribution and possible complete failure of the part.

And too much resin is not good for the structural integrity of the final composite part. Therefore, researching the optimal ratio of resin to reinforcing fibers is indispensable to obtain the most effective composite structural parts.

2. Reinforcing fiber selection

The physical properties and differences of the three reinforcing fibers of aramid fiber, carbon fiber and glass fiber can be easily checked. More research is needed on how to incorporate these fiber properties into the fabric, which is related to the final material properties of the fabric after lamination, each type of fiber and fabric has its own unique advantages, such as optimal carbon fiber performance, glass fiber cost minimum etc.

In order to achieve lightweight composite structures, using carbon or aramid fibers instead of glass fibers will easily reduce the weight of any component because aramid fibers and carbon fibers are lighter and stronger compared to glass fibers, resulting in lighter components .

3. Use Unidirectional belt

Reducing part weight requires understanding the details of the part's usage. It is important to know how and where to apply the load. Once the technical requirements and design details of the part are understood, fiber orientation plays an integral role in part weight optimization.

Unidirectional tapes provide excellent performance in a single direction for carrying loads in a given direction, and their use in composites allows for optimized strength where needed. This is a viable option to increase the stiffness and strength of the part without adding weight.

4. Resin selection

In terms of overall strength and high modulus applications, the highest performing ambient temperature resin is epoxy resin, which outperforms polyester and vinylester resins significantly, especially when used with carbon or aramid fibers. Higher strength-to-weight ratio (mostly polyester resins are used for part flexibility).

Epoxy resins generally have a range of options, which requires consulting the manufacturer's technical data sheet to find the resin material properties that meet the design needs. Likewise, achieving the proper ratio of resin to fiber in the selected epoxy resin will result in the most efficient composite material.

5. Optimization of composite materials

The best way to get the lightest composite parts is to use prepreg. The resin in the prepreg has been combined with the fiber in advance and has reached the limit of the material performance. Because the fiber to resin ratio has been optimized, it produces products that are clearly superior to wet layup or infusion processes.

The prepreg cured layer density is relatively deterministic, so a product designed from a prepreg perspective is accurate in weight and repeatability with the design of the final part. Accurate data for wet layup and infusion processes at the design stage depends on several process factors.

6. Add sandwich structure

Adding materials doesn't seem to be good for saving weight and getting lighter parts. Adding a core to an existing design will increase the weight of the stack. However, core materials are often used to strengthen parts and add high stiffness to composite parts. Some core types add weight to the resin as well as stiffness, while some core types are designed to achieve the highest degree of composite performance.

Properly adding cores to weaker areas of a part is known to make the part stronger. Of all the cores available, the Nomex honeycomb core construction provides excellent performance, with Nomex Honeycomb it may require more processing, but given the weight strength it achieves, the results are undeniable. The core can also be replaced from a heavier, resin-impregnated core to a lighter core, and weight can be easily reduced in this way.