Application Of Marine Composite Materials (carbon Fiber/fiberglass/aramid)
At present, carbon fiber composite materials have been widely used in aerospace, sports and leisure, automotive industry, environmental energy, civil engineering and other fields, and its application range is almost everywhere. Among them, in small boats, yachts, large ships and other ship fields, carbon fiber Applications are progressing. Carbon fiber is an ideal material for marine applications, as it can reduce hull vibration, maintain a good wireless communication environment between ships, etc.
In addition, the most important reason to use carbon fiber is that the material can improve the speed and fuel economy of ships by reducing weight. For example, by replacing glass fiber composites (GFRP) with carbon fiber reinforced composites (CFRP), the weight of the hull can be reduced.
The application of carbon fiber and its composite materials in yachts, through the use of CFRP in the superstructure and deck equipment, can further reduce weight and improve the stability of the ship; carbon fiber drive shafts can also reduce weight and reduce vibration; carbon fiber in propeller blades There are also potential wide-ranging applications.
As early as the 1940s, the US Navy used composite materials to build small ships, which opened a new chapter in ship construction. In the mid-1950s, it was stipulated that ships under 16m must be made of composite materials. With the development of material science, the improvement of construction methods and application forms, in 1994, the United States used composite materials to build a 68.3-meter-long "Avenger"-class minesweeper. The deep-dive exploration boat built in 1996 is made of graphite fiber-reinforced composite materials for its shell, and the diving depth of the boat can reach 6096m. The "Stiletto" code-named M80 manufactured in 2006 is the latest high-speed stealth test speedboat and the largest hull formed by carbon fiber at one time. With a length of 24.4m and a width of 12.2m, the draft is only 0.9m and the displacement is 67t, which enables the speedboat to easily obtain a higher speed. The Los Angeles-class nuclear submarine of the United States also uses a new type of composite material to make a sonar dome, which is 7.6m long, 8.1m in maximum diameter, and has excellent performance. The U.S. Navy is also developing military-equipped ships into traditional hovercraft. Conventional hovercraft uses aluminum rigid shells similar to aircraft as the base material, while the American All Terrain Amphibious Hovercraft Company (ATLAS Hovercraft) has developed an all-composite hovercraft called AH-100-P, which is designed to accommodate 150 crew.
As a major country in the manufacture of composite ships in Asia, Japan began to build FRP ships as early as 1953. In the 1970s, Japanese fishing boats began to widely use FRP. Since then, Japan has manufactured tens of thousands of FRP fishing boats every year. more and more perfect. Today, Japan's FRP production ranks among the top in the world, and the FRP consumption of marine motorized fishing boats alone accounts for 76.3%. At the same time, in the development and production of high-performance composite materials such as carbon fiber, Japan also occupies an important position in the world. Its high-performance ships, racing boats and luxury yachts now widely use high-performance carbon fiber composite materials.
Carbon fiber has two types of high strength and high modulus. It has the characteristics of high stiffness, high yield strength and high bending strength. It is generally used in the manufacture of high-performance and high-speed ships. Japanese carbon fiber is sold all over the world and is mainly used in the manufacture of high-speed speedboats, high-performance racing boats, luxury yachts and other boats.
Aramid fiber has the characteristics of high specific strength, high toughness, impact resistance and bulletproof, and is used for boat components with high requirements for tensile, active load and bulletproof. Due to the low compressive bending strength, it is not suitable for the manufacture of high-compression and high-bending hulls, and is only suitable for ships with strict weight limits.
When considering the cost in the manufacture of boats, under the premise of meeting the design requirements, a design method using hybrid fiber composite materials has emerged. The mixed use of a variety of fiber reinforced materials overcomes some of the shortcomings of a single fiber composite material, improves the physical and mechanical properties, and further improves the designability of the material. The two-dimensional and three-dimensional fabrics formed by reinforcing materials can be manufactured according to the design needs to meet the strength, intra-layer and inter-layer performance of ships, and further achieve the requirements of light weight and high strength for ships
Due to the light weight of composite materials, the US Navy plans to use glass-reinforced phenolic composite materials in the power compartment, including cylinders, cylinder heads, oil pans, cam covers, support rollers, speed control sprockets, and water pumps, oil pumps, and pulleys of marine diesel engines. Wait.
Some mechanical elements of surface ships can also be made of composite materials, and in the trend to reduce the weight of the hull, the weight reduction of the power transmission components of the propulsion system is also on the agenda. Typically, on high-speed boats where 2 or 4 high-speed diesel engines drive the waterjet through a reduction gearbox, the distance between the diesel engine and the gearbox or between the gearbox and the waterjet is shortened. Especially in the narrow space of the catamaran, 4 diesel engines are required to be arranged in a staggered manner, and the power generated by the front diesel engine must be transmitted through the rear diesel engine. Therefore, this requires a transmission with the lightest weight and the fewest components. The use of the drive shaft made of carbon fiber tube material can easily achieve the purpose of reducing the weight of the transmission components.
The main advantages of CFRP drive shafts include: significantly reduce the weight of the drive shaft; high critical speed, usually do not need to arrange bearings on long shafting, reduce the number of bearings, reduce costs, reduce shafting, reduce parts, Save the cost of bearing supports and reduce weight; corrosion resistance, low magnetic signal, electrical signal, anti-wear, can reduce the noise in structure and air by 520dB. (Source: Easy Composites / Composites Xintiandi)
