What is the development direction of the application of carbon fiber composite materials in the field of military ships? Now more and more people realize that carbon fiber is an important material for the development of national defense and the national economy, which is a technology-intensive key material, and the carbon fiber industry is also a strategic emerging industry that is the focus of national development. Carbon fiber composites (CFRP) have very high specific strength and stiffness, and are ideal materials for large integrated structures, and have important application significance in military aircraft, military ships and so on.

 

 

 

1. Carbon fiber superstructure

 

 

 

Composite materials have been used in the gunboat deckhouses on patrol gunboats since the mid-1960s, and in the early 1970s, composite materials were also used in the superstructure of mine-hunting boats. The Royal Finnish Navy's fast patrol boat Rauma also has a composite sandwich structure for the superstructure and aluminum alloy for the hull.

 

 

 

Compared to steel and aluminum, carbon fiber superstructure has many disadvantages, such as high manufacturing costs, because of the expensive connection to the steel deck, for medium frigates, the superstructure of carbon fiber composite instead of steel can increase construction costs by 50-150%, although many ship builders and navies have begun to accept higher manufacturing costs. Because you can save life cycle costs, thereby reducing the overall cost.

 

 

 

2, carbon fiber propeller

 

 

 

The propeller material of naval ships has always been nickel-aluminum-copper alloy, which has many problems, such as the high cost of machining complex blades, the blades are easy to fatigue and crack, the acoustic damping is relatively poor, and the vibration will bring noise and so on. So naval designers have had to consider other materials, most notably stainless steel, titanium and carbon fiber.

 

 

 

The design and performance of carbon fiber propeller systems are highly confidential, and the research progress in recent years has not been publicly published. However, it is known that the fibers in carbon fiber blades can withstand major hydrodynamic and centrifugal forces. A large number of naval ships are currently fitted with carbon fiber propellers, such as landing ships and minesweepers, and carbon fiber propellers are also used in torpedoes and small ships.

 

 

 

3. Carbon fiber mast

 

 

 

Composite materials were first used in masts in the 1960s. The traditional steel masts have an open structure and protrude, which interferes with the ship's radar and communications systems and is prone to corrosion. The U.S. Navy began developing the Advanced fully enclosed Mast/Sensor System (AEM/S) in 1995, and the entire structure is 28m high and 10.7m in diameter, making it the largest carbon fiber overwater structure on a U.S. Navy ship.

 

 

 

4, carbon fiber propulsion shaft

 

 

 

In the trend of reducing the weight of the hull, the weight reduction of the power transmission components of the propulsion system is also mentioned on the agenda. Typically, on a high-speed ship with two or four high-speed diesel engines driving the water jet through a reduction gearbox, the distance between the diesel engine and the gearbox and the water jet propulsion unit is shortened.

 

 

 

In particular, in the narrow space of the catamaran, four diesel engines are required to be arranged at random, and the power emitted in the front diesel engine must be transmitted through the rear diesel engine. Therefore, this requires the transmission with the lightest weight and the fewest components. The drive shaft made of carbon fiber composite material can easily achieve the purpose of reducing the weight of the transmission components.

 

 

 

5. Other components

 

 

 

Many navies are considering carbon fiber composites for use in weapon covers and deck shields, as well as as missile impact shields to protect against high velocity projectiles and shrapnel. Some experts are also developing the use of carbon fiber composite materials in ship bulkheads, doors and decks.

 

 

 

At present, carbon fiber is widely used in naval ships. However, most of the mature technology is only applied to relatively small naval vessels, such as frigates, patrol boats, MCMV, etc., or some non-structural, non-critical components of large ships. It is believed that with the development and progress of science and technology, the application of carbon fiber composite materials on naval ships will be increasingly mature, and the application range will be more and more extensive