Advanced composite materials (Advanced Composites,ACM) refer to composite materials that can be used to process main bearing structure and secondary bearing structure, and their stiffness and strength performance are equivalent to or exceed that of aluminum alloy. At present, it mainly refers to boron fiber, carbon fiber, aramid fiber and other reinforced composite materials with higher strength and modulus. Carbon fiber composite material has the characteristics of light weight, good ductility, high specific strength, heat conduction, high and low temperature resistance, corrosion and heat insulation, vibration attenuation, unique electromagnetic wave permeability, wave-absorbing concealment and workability, etc, it is commonly used in the field of aerospace.
Carbon fiber composites are of great value in military applications such as aerospace. For example, in terms of military airplanes and satellites, not only the material is required to be light, but also the strength is required to be very high; In terms of medical devices, the material is required to have high x-ray permeability and good biocompatibility with human body; in terms of military vessels, they should be high-pressure resistant and corrosion resistant. Facing these harsh requirements, only with the help of advanced composite technology can we solve them.
The value of saving structural quality on different aircrafts is different, but in order to achieve the goal of weight loss, Besides optimizing structural form, adopting materials with high specific strength and high specific modulus is almost the only way. Suzhou nuoen composite material uses carbon fiber composite material to customize carbon fiber components for a domestic unmanned aerial vehicle manufacturer. According to the acceptance feedback of the manufacturer, the design strength of this carbon fiber unmanned aerial vehicle component meets the demand of unmanned aerial vehicle use, the overall weight intersection the weight of the traditional unmanned aerial vehicle is reduced by about 40%, which greatly improves the flight mileage and flight speed of the unmanned aerial vehicle, and fully verifies the superiority of carbon fiber in light weight.
The carbon fiber composite material shows remarkable specificity, that is, many properties along the fiber axis direction and perpendicular to the fiber axis direction, including light, electricity, magnetism, heat conduction, specific heat, there are significant differences in thermal expansion and mechanical properties.
Although the specificity of materials brings troubles to the calculation of material properties, it also brings more freedom to the design. Due to the heterosexual characteristics of carbon fiber composite bedding, the bedding orientation can be adjusted in a wide range, therefore, the elasticity and strength characteristics of carbon fiber composites can be changed by changing the orientation and stacking sequence of the layers, so as to obtain the structure of carbon fiber composites which meets the use requirements and has the best performance quality ratio.
The mechanical properties of carbon fiber composites have coupling effects that metal materials do not have. For example, when the one-way plate is stretched in the non-principal axis direction, it will cause shear deformation, namely tension-shear coupling; When the one-way plate is bent in the non-principal axis direction, it will cause torsion deformation, that is, bending and torsion coupling. The ingenious application of coupling effect of carbon fiber composite materials can solve the problems of torsion deformation and diffusion existing in the design of the wing of the front-wing aircraft, while using metal materials, these problems are difficult to solve.
Fatigue damage is low stress damage caused by crack formation and expansion under alternating load. There are countless fiber resin interfaces in carbon fiber Fiber Composites, which can prevent further crack expansion, thus delaying the occurrence of fatigue damage. The tensile/compressive fatigue limit of carbon fiber composites reaches 70% ~ 80% of the static load, while the fatigue limit of most metal materials is only 40% ~ 50% of the static strength.
In the forming process of resin-based composites, due to the complexity of polymer chemical reactions, theoretical analysis and mechanism prediction often have many difficulties. However, for mass production, when the process specification is determined, the manufacture of composite components is relatively simple.
Many methods can be applied to the forming of composite components, such as using drawing, injection, winding and laying technologies, including integral co-curing forming and RTM(Resin Transfer Molding) forming, this kind of forming technology greatly reduces the number of parts and fasteners, simplifies the lengthy production process of metal sheet metal parts in the past, shortens the production cycle, and is easy to realize forming automation. The size of composite parts is not limited by the size of metallurgical rolling plate equipment, processing and forming equipment.
The above characteristics make carbon fiber composites get key applications in the field of aerospace. Accordingly, these characteristics also help us solve many design problems in the field of aerospace. As there is still a certain gap between domestic carbon fiber technology and foreign carbon fiber technology, more in-depth research is needed if carbon fiber composite materials are to be applied to more fields.
