Application of carbon fiber composite materials in the ocean

Carbon fiber composite material is a fiber reinforced material made of carbon fiber and resin, metal, ceramics and other matrix. Because of its light weight, high strength, high temperature resistance, etc., it has been widely used in aerospace, sports and leisure, high-speed rail in recent years. In the fields of automobiles and civil engineering. Carbon fiber composite materials have excellent fatigue resistance, corrosion resistance and excellent construction performance due to high strength and high strength, which makes it suitable for marine applications with special requirements on material properties. watch for. In recent years, carbon fiber composites have played an increasingly important role in shipbuilding, offshore energy development, and marine engineering repair.

1.Application on board
Carbon fiber composites have a natural advantage over traditional shipbuilding materials. First, carbon fiber composites have good mechanical properties. The hull is manufactured with 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 cost is much lower than that of the steel ship. At the same time, since the interface between the carbon fiber and the resin matrix can effectively prevent the crack propagation, the material has good fatigue resistance; in addition, due to the chemical inertness of the carbon fiber surface, the hull has the characteristics that the aquatic organism is difficult to epiphytic and corrosion resistant, which is also the ship construction. One of the most important factors in selecting materials. Therefore, carbon fiber composite materials have unique comprehensive performance advantages in shipbuilding, and are now widely used in this field. At the same time, the development of the carbon fiber industry has been promoted from the application field expansion.

1.1Military ships

Carbon fiber composites have good acoustic, magnetic and electrical properties: they are transparent, sound-permeable and non-magnetic, so they can be used to improve the stealth performance of warships. The use of composite materials in the superstructure of the ship not only reduces the weight of the hull, but also transmits and receives electromagnetic waves at a predetermined frequency by shielding the frequency selective layer embedded in the interlayer to shield the enemy’s radar electromagnetic waves. . For example, the “skjold” class cruiser built by the Norwegian Navy in 1999 used a sandwich composite consisting of a polyvinyl chloride foam core layer, glass fiber and carbon fiber interlayer. This design not only improves the strength-to-weight ratio, but also has good impact resistance. The performance also greatly enhances the characteristics of low magnetic, anti-infrared and anti-radar scanning. The Swedish Visby-class frigates, which were commissioned in 2000, all use carbon fiber composite materials, which have special functions of weight reduction, radar and infrared double stealth.

The application of carbon fiber reinforced composite masts on ships has gradually emerged. The LPD-17 ship, which was commissioned in the United States in 2006, uses a carbon fiber/Balsa core advanced composite composite mast. Unlike the original open mast, the LPD-17 uses a new fully enclosed mast/sensing system. (AEM/S), the upper part of this carbon fiber composite mast covers the frequency selective surface material (FSS), allowing waves with a specific frequency to pass through, and the lower half can reflect radar waves or be absorbed by radar absorbing materials. . Therefore, it has good radar stealth and detection functions. In addition, various antennas and related equipment are uniformly combined in the structure, which is not easy to be corroded, and is more conducive to the maintenance of the equipment. The European Navy has developed a similar closed-integrated sensor mast made of nanofiber-made glass fiber combined with carbon fiber as a reinforcement. It allows various radar beams and communication signals to pass undisturbed with each other, and the loss is extremely low. In 2006, this advanced technology mast ATM was used on the British Navy’s “Royal Ark” aircraft carrier.

Carbon fiber composites can also be used in other aspects of the ship. For example, it can be used as a propeller and propulsion shafting system in the propulsion system to mitigate the vibration effects and noise of the hull, and is mostly used in reconnaissance ships and fast cruise ships. It can be used as a rudder in machinery and equipment, some special mechanical devices and piping systems. In addition, high-strength carbon fiber ropes are also widely used in naval warship cables and other military items.

1.2Civil yachts

Large yachts are generally privately owned and expensive, requiring light weight, high strength and durability. Carbon fiber composites can be used in yachts’ instrument dials and antennas, rudders, and in reinforced structures such as decks, cabins, and ship’s bulkheads. The traditional composite yacht is mainly made of FRP, but due to insufficient rigidity, the hull is often too heavy after meeting the rigidity design requirements, and the glass fiber is a carcinogen, which is gradually banned abroad. The proportion of carbon fiber composites used in today’s composite yachts has increased significantly, and some have even used carbon fiber composites. For example, Baltic’s super-yacht “Panama” double-barge, the hull and deck are sandwiched with carbon fiber / epoxy resin skin, Nomex  honeycomb and CorecellTM structural foam core, the hull is 60m long. But the total weight is only 210t. The Sunreef 80 Levante, a carbon fiber catamaran built by the Polish catamaran’s Sunreef Yachts, uses vinyl ester resin sandwich composites, PVC foam and carbon fiber composites. The mast booms are custom carbon fiber composites, and only part of the hull uses FRP. . The no-load weight is only 45t. Fast speed, low fuel consumption and excellent performance.

The “Zhongke·Lianya” yacht built in 2014 is currently the only full-carbon fiber yacht in China. It is a green yacht made of a combination of carbon fiber and epoxy resin. It is 30% lighter than the same type of fiberglass yacht and has higher strength, faster speed and lower fuel consumption.

In addition, the yacht’s cables and cables use high-strength carbon fiber ropes to ensure safety. Since the carbon fiber has a tensile modulus higher than that of steel and a tensile strength of several times or even tens of times, and has the woven property of the fiber, the carbon fiber rope is used as a base material, which can make up for the steel wire rope and the organic polymer rope. Insufficient.z
2. Application in marine energy development

2.1 Submarine oil and gas fields

In recent years, carbon fiber composite materials have become more and more widely used in the field of marine oil and gas development. Corrosion in the marine environment, high shear, and strong shearing caused by undercurrent flow of the water impose strict requirements on the corrosion resistance, strength and fatigue properties of the material. Carbon fiber composites have obvious advantages in light, durable and anti-corrosion in the development of offshore oil fields: a 1500m water depth drilling platform has a steel cable with a mass of about 6500t, while the carbon fiber composite density is ordinary steel. 1/4, if the carbon fiber composite material is used to replace part of the steel, the load capacity of the drilling platform will be significantly reduced, and the construction cost of the platform will be saved. The reciprocating motion of the sucker rod will easily lead to material fatigue due to the unbalanced pressure between the seawater and the pressure inside the tube. Breaking, and using carbon fiber composite material can solve this problem; due to the corrosion resistance of seawater environment, its service life in seawater is longer than steel, and the depth of use is deeper.

Carbon fiber composites can be used as production well pipes, sucker rods, storage tanks, submarine pipelines, decks, etc. in oilfield drilling platforms. The manufacturing process is divided into a pultrusion process and a wet winding process. Pultrusion is generally used on common pipes and connecting pipes. The winding method is generally used as the surface of the storage tank and the pressure vessel, and can also be used in an anisotropic flexible pipe in which the carbon fiber composite material is wound and arranged at a specific angle in the armor layer.

The continuous sucker rod of carbon fiber composite material is a ribbon-like structure similar to film and has good flexibility. Produced and applied by the United States in the 1990s. It is made of carbon fiber as reinforcing fiber and unsaturated resin as base material. It is produced by pultrusion process after cross-linking curing at high temperature. From 2001 to 2003, China used a carbon fiber sucker rod and an ordinary steel sucker rod in the pure beam oil field to make a pilot. The use of carbon fiber sucker rod can significantly increase the oil output and reduce the load of the motor, which is more energy efficient. Moreover, the carbon fiber composite sucker rod is more resistant to fatigue and corrosion resistance than the steel sucker rod, and is more suitable for application in the development of subsea oil fields.

2.2 Offshore wind power

The abundant wind power resources on the sea is an important area for future development and the most advanced and demanding field of wind power technology. China’s coastline is about 1800km and there are more than 6,000 islands. The southeast coast and island regions are rich in wind resources and easy to develop. In recent years, efforts to promote the development of offshore wind power have been supported by relevant departments. More than 90% of the weight of wind power blades consists of composite materials. Large winds at sea and high power generation are bound to require larger blades and better specific strength and durability. Obviously, carbon fiber composite materials can meet the requirements of developing large-scale, lightweight, high-performance, low-cost power generation blades, and are more suitable for marine applications than glass fiber composite materials.

Carbon fiber composites have significant advantages in marine wind power generation. The carbon fiber composite blade has low quality and high rigidity, and the modulus is 3 to 8 times that of the glass fiber product; the humidity is large under the marine environment, the climate is changeable, and the fan works for 24 hours. The blade has good fatigue resistance and can resist the bad weather. It improves the aerodynamic performance of the blade and 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. The conductive performance, through special structural design, can effectively avoid the damage caused by lightning strike on the blade; reduce the manufacturing and transportation cost of the wind turbine blade; and have vibration damping characteristics.

3.Marine engineering applications

Carbon fiber composite materials are used in marine engineering buildings. They mainly use the characteristics of light weight, high strength and corrosion resistance, and replace traditional steel building materials in the form of tendons and structural parts to solve the problem of high transportation cost of seawater erosion steel and transportation. It has been applied to offshore island reef buildings, docks, floating platforms, light towers, etc. The use of carbon fiber composites for engineering restoration began in the 1980s, and Mitsubishi Chemical Corporation of Japan took the lead in researching the mechanical properties of carbon fiber composites and their application in engineering reinforcement. The initial research focus was on the reinforcement of reinforced concrete beams using carbon fiber composites, which later evolved into reinforcement and reinforcement of various civil engineering. The repair of offshore oil platforms and ports by carbon fiber composites is only one aspect of its application. There are many related documents. It is worth mentioning that the US DFI company used carbon fiber rods to repair the Navy Pearl Harbor terminal. At that time, the technicians used innovative carbon fiber rods to repair the reinforcement. The carbon fiber rod repaired dock can withstand 9t steel from 2.5m high. It falls off without being damaged, and the enhancement effect is obvious.

As for the application of carbon fiber composites in marine engineering, there is also a type of repair and reinforcement of submarine pipelines or columns. Traditional maintenance methods such as welding, weld improvement, clamps, grouting, etc. have their own limitations, and the use of these methods is more restricted in the marine environment. The repair of carbon fiber composites is mainly made of high-strength and high-adhesive resin materials such as carbon fiber cloth and epoxy resin, which are adhered to the repairing surface, so it is thin and light, high-strength, good in durability, convenient in construction, and adaptable to different shapes. Has a significant advantage.

Post time: Mar-23-2019

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