Unmanned Aerial Vehicles – Classification, Types of Composite Materials Used in Their Structure and Applications

Unmanned aerial vehicles (UAV) or drones, due to their versatility can be used in a wide range of applications, from army missions to industrial ones. With all these capabilities, the widespread use of drones in smart cities is limited, due to problems and concerns related to safety (their crash for technical reasons, collision in the air with other planes, extreme natural weather), confidentiality (hackers can use malicious applications to exploit and obtain personal data / profiles of people using the wireless location method) and security (thanks to the technology inside the drone-GPS, Wi-Fi that could be hacked/destroyed by attackers). Currently there are many types of drones classified by size, weight, altitude, endurance, landing method (VTOL, HTOL), etc. However, these parameters vary depending on the application of the drone. The performance of drones is focused on the type of built-in electronics but also on the material used to make it. All modern drones are equipped with a series of sensors and other communication systems, increasing inevitably the total weight and reducing the flight time. Therefore, weight reduction is a vital parameter to build the drone's body/structure (generally using thermosetting fibers and resins) without compromising their resistance. Thus, high strength-to-weight ratio, facilitates maneuverability, reduces energy consumption, increases the ability to carry more payload, flight time, etc. The use of composites compared to aluminum reduces weight by 15-45%, increases corrosion, fatigue, impact resistance, reduces noise and vibrations. The composites most used for manufacturing the structure of UAVs (fuselage, wing, landing gear) are: polymers reinforced with carbon fibers (CFRP), polymers reinforced with fiberglass (GFRP), boron and aramid fibers.