Several Methods for Weight Reduction of Unmanned Aerial Vehicle Using Carbon Fiber Composites

Small UAVs generally have the disadvantages of low load, low flying altitude, slow speed and short endurance. Because of the complex working environment and high damage frequency of the airframe, the traditional metal materials such as aluminium alloy can not meet the development needs of UAVs in terms of performance. Carbon fiber reinforced composites (CFRP) have high specific strength and stiffness, which can greatly reduce the weight of UAV fuselage, reduce the load cost and increase the payload of UAV, prolong the flight distance and time of UAV, which is of great significance to the lightweight, miniaturization and high performance of UAV structure, and become an ideal material for the new generation of UAV. As far as materials are concerned, carbon fibre composites can reduce weight by at least 30% compared with aluminium alloys. However, in practical applications, to maximize the lightweight advantages of carbon fibre composites, we need to start from the following aspects.

Layer design is used to reduce weight: _carbon fiber composites have high anisotropy, the elastic modulus and strength of composites in the longitudinal direction (fiber direction) are strong, while the elastic modulus and strength in the transverse direction (vertical fiber direction) are relatively weak. Through the reasonable design of the ply structure and the coupling effect of the asymmetric and unbalanced ply of the composite material, the structural stiffness and structural elasticity of the composite material can be perfectly combined, so that the dominant mechanical properties of the carbon fiber composite material can be arranged along the transmission path of the structure, thus effectively utilizing the bearing capacity of each tow and maximizing its mechanical properties. Ability advantage.

 

Sandwich sandwich structure is also an important method of structural weight reduction. Sandwich sandwich structure is to attach thin but rigid panels on both sides of relatively thick core material. When this structure is subjected to bending loads, there is a certain distance between the upper and lower panels. On the contrary, the structure can obtain a larger proportion of rigidity. Carbon fiber reinforced composites (CFRP) are used as skin, and light foam plastics with certain hardness and compression resistance, such as XPS, EPP, PMI, are selected as core materials to form a composite sandwich structure of CFRP-core-CFRP.

This sandwich sandwich structure can significantly reduce the weight while maintaining the mechanical properties. Especially, it can also reduce the cost to a certain extent. This method is mostly used in large UAV components, and is also common in carbon fiber medical beds. It is also a scheme that can be considered in small UAV.