Application of composite structure in UAV field

Polyacrylonitrile based carbon fiber and Nomex honeycomb material are widely used in the body shell, wing skin and leading edge of UAVs. Foam sandwich composite made of PAN-based carbon fiber plate and foam material or polyacrylonitrile based carbon fiber tube is widely used as the main beam of UAV. Kevlar fiber materials are applied to propellers, fuselages, connectors and other parts to significantly improve fatigue strength and impact resistance.

The main bearing structure of medium and large UAV is made of metal, the rest is made of composite materials, small and medium-sized UAV is made of carbon fiber, glass fiber and its hybrid materials, and unmanned fighter aircraft is made of carbon fiber composite material, aramid fiber and so on. Small, low-speed drones are made of carbon fiber, aramid fiber, paper honeycomb and wood.

Because the UAV does not need to consider the limitation of human physiological bearing capacity in the structural design, it can be more focused on the design of the maneuvering performance of the UAV, so that it has some characteristics in the selection of materials that are different from manned aircraft. The application of composite materials can greatly improve the stealth ability of the body.

First, because the polymer is not conductive, it can avoid the formation of the scattering field of the probe wave. Secondly, the application of composite materials plays a very important role in the effective combination of structure and function. For example, through the application of structural stealth materials, the body's reflection of radar detection waves can be greatly reduced. Finally, the application of composite materials can achieve the integrity of the body, so as to achieve the purpose of stealth through smooth and integrated structural design, avoiding the scattering of detection waves caused by joints, nails and other non-smooth design. All in all, these designs effectively improve the stealth of drones.

According to statistics, at present, countries around the world are largely using advanced composite materials based on carbon fiber composites on drones, accounting for 60%-80% of the total mass fraction of the structure; Reduce body mass by more than 25%. From the beginning of the non-bearing structure, more and more bearing structures of UAVs are designed and manufactured using carbon fiber composite structures.