Application of carbon fiber in marine field

In recent years, the application of carbon fiber composite materials in the marine field has become more and more extensive. The corrosion in the marine environment, high pressure, and strong shear caused by underwater undercurrent flow have put forward strict requirements on the corrosion resistance, strength and fatigue properties of the materials. Carbon fiber composite materials themselves have excellent fatigue resistance and corrosion resistance, and they have an advantage in the development and expansion of the marine field. Nowadays, carbon fiber composite materials are playing an increasingly important role in the marine field.

Application in the construction of submarine oil and gas fields

Carbon fiber composite materials can be used as production well pipes, sucker rods, storage tanks, subsea oil pipelines, decks and other components in oilfield drilling platforms. Its manufacturing process is divided into pultrusion process and wet winding process. Pultrusion is generally used on common pipes and connecting pipes. The winding method is generally used as the surface of storage tanks and pressure vessels, and can also be used in anisotropic flexible pipes. Carbon fiber composite materials can be wound at a specific angle and arranged in the armor layer.

For a drilling platform with a water depth of 1500m, the weight of the steel mooring cable is about 6500t, but the density of carbon fiber composite material is 1/4 of that of ordinary steel. If carbon fiber composite materials are used to replace part of the steel, the heavy load of the drilling platform will be significantly reduced, and the construction cost of the platform can be saved to a certain extent. The sucker rod needs to reciprocate during the operation. Due to the imbalance between the seawater pressure outside the pipe and the pressure inside the pipe, it is easy to cause fatigue fracture of the material, but carbon fiber composite materials can solve this problem. Due to the corrosion resistance of the seawater environment, carbon fiber composite materials have a longer service life than steel in sea water and can achieve deeper service depths.

Application in offshore wind power

More than 90% of the weight of wind turbine blades is composed of composite materials. The offshore wind is large and the power generation is large, which is bound to require larger blades with better specific strength and durability. Carbon fiber composite materials have high specific strength and specific stiffness, which can meet the requirements of developing large-scale, lightweight, high-performance, and low-cost power generation blades. Compared with glass fiber composite materials, carbon fiber composite materials are more suitable for use in the marine field.

Carbon fiber composites have significant advantages in offshore wind power generation. Carbon fiber composite blades have low weight and high stiffness, and the modulus is 3-8 times that of glass fiber products; The blades made of carbon fiber could  24 hours long continuously work in the marine environment with high humidity and changeable climate. The blade has good fatigue resistance and can better withstand severe weather, improves the aerodynamic performance of the blade, reduces the load on the tower and the axle, so that the output power of the fan is smoother and more balanced, and the energy efficiency is improved; Using the electrical conductivity of carbon fiber and through special structural design, it can effectively avoid damage to the blade caused by lightning strikes; reduce the manufacturing and transportation costs of wind turbine blades; it has vibration damping properties, etc.

Application on ships

Carbon fiber composites have good mechanical properties. Using it to manufacture the hull has the characteristics of light weight and low fuel consumption, and the construction process is relatively simple, the cycle is short, and the molding is convenient, so the construction and maintenance costs are much lower than that of steel ships.

At the same time, because the interface between the carbon fiber and the resin matrix can effectively prevent crack propagation,so  the material has good fatigue resistance; In addition, due to the chemical inertness of the carbon fiber surface, the hull has the characteristics that aquatic organisms are difficult to adhere to and are resistant to corrosion, which is also one of the very important factors in the selection of materials for ship construction.

Therefore, carbon fiber composite materials have unique comprehensive performance advantages in shipbuilding, and are currently being widely used in this field. At the same time, the expansion of application fields has driven the development of the carbon fiber industry.

Application in marine engineering

Carbon fiber has been used in offshore reef buildings, docks, floating platforms, lighthouse towers, etc. Carbon fiber composite materials are used in marine engineering buildings because of their light weight, high strength and corrosion resistance characteristics. They replace traditional steel building materials in the form of rope and structural parts, and solve the problems of seawater erosion of steel bars and high transportation costs in long distances.

Regarding the application of carbon fiber composite materials in marine engineering, there is another category of repair and reinforcement of submarine pipelines or pipe strings. The repair refers to sticking carbon fiber cloth to damaged surface with high-strength and high-adhesive resin materials such like epoxy resin. Therefore, it has obvious advantages such as thin and light, high strength, good durability, convenient construction and adaptability to different shapes.

The use of carbon fiber composite materials for engineering repair began in the 1980s. Japan's Mitsubishi Chemical Company took the lead in researching the mechanical properties of carbon fiber composite materials and its application in engineering reinforcement. The initial research focus was on the reinforcement of concrete beams using carbon fiber composite materials, and later developed to the reinforcement of various civil engineering.

The excellent properties of carbon fiber composites make it have broad application prospects in the field of marine applications. Generally speaking, compared with the mature applications in aerospace and other fields, the application of carbon fiber in the marine field started relatively late. At the same time, the high cost of carbon fiber is also an important factor restricting its large-scale application. With the developing of marine resources, vigorously promoting the application of carbon fiber in the marine field is an inevitable trend of development. On the other hand, the increasing demand for carbon fiber composite materials in the marine field will also promote the healthy development of the carbon fiber industry chain in terms of application traction.