Following the tragic implosion of the Titan submersible that resulted in five fatalities, they have introduced an ultra-strong carbon fiber hull for mass-producing high-performance underwater drones. Interestingly OceanGate, the company that built the Titan, pioneered the use of carbon fiber in the hull of a deep-sea submersible. However, there’s been much criticism over the decision to use this material for the craft’s hull, with several claims this is the reason for the implosion.
The scientists behind these new eco-friendly submarine drones say that they chose to use of ultra-strong carbon fiber, because it’s suitable for shallow seas and capable of withstanding pressures at depths up to 6,000 meters (19,700 feet), promises enhanced performance and reduced manufacturing costs, according to the researchers involved.
This technological breakthrough challenges the belief that carbon fiber is unsuitable for underwater use and could potentially give China an advantage in the drone competition in strategic areas like the Taiwan Strait and the South China Sea. High-performance underwater drones are advanced unmanned vehicles designed to operate efficiently underwater for various applications.
These drones utilize cutting-edge technologies to navigate, collect data, perform tasks, and operate autonomously or under remote human supervision. Carbon fiber’s use in submarines has been limited due to several reasons. Firstly, manufacturing carbon fibers is typically more expensive than traditional materials like steel used in submarine construction. Secondly, carbon fibers can be brittle, especially under impacts or cyclic loading, which is a concern in underwater environments where submarines encounter obstacles or debris.
This brittleness was tragically demonstrated in the implosion of the Titan submersible, the world’s first crewed carbon fiber submersible. Operated by the American company OceanGate, it collapsed under immense water pressure during a dive to the Titanic wreck at a depth of 4,000 meters, resulting in the loss of all five crew members in June of last year.
Despite these challenges, Chinese scientists have recognized the potential of eco-friendly carbon fiber materials for underwater operations. The advantages include improved buoyancy and maneuverability, crucial for enhancing operational efficiency and performance. Carbon fiber composites also offer a high strength-to-weight ratio, providing comparable or superior strength to steel while being significantly lighter, along with corrosion resistance.
In a peer-reviewed paper published in the Chinese journal Fibre Composites in June 2024, senior engineer Guo Yuqi from the Harbin FRP Research Institute revealed that the carbon fiber hulls of Chinese drones are approximately 3cm thick, one-quarter the thickness of Titan’s hull. They estimate the hulls can withstand pressures up to 90 MPa, equivalent to nearly 9,000 meters ocean depth, although they have set the operational depth at 6,000 meters for safety reasons, corresponding to 60 MPa pressure.
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Laboratory tests have demonstrated the strength of these eco-friendly drones, withstanding water pressures of up to 77 MPa, more than double what Titan’s hull could withstand in similar tests at the University of Washington. To address fatigue issues, especially pressure and temperature variations, the front and rear ends of the carbon fiber pressure hulls are reinforced with T4 titanium alloy material. Additionally, a 1mm waterproof coating provides protection against leaks, damage, and cracking during normal use.
In another paper published in the same journal in May, Guo and his team emphasized the importance of underwater submersibles in safeguarding national marine rights, interests, and resource security. They stated that the technological advancement of these drones reflects national defense capabilities and technological prowess. Given China’s substantial production capacity for carbon fiber, which supplies nearly half of the world’s production, experts anticipate further price reductions as new production lines come online in the coming years.
This trend could significantly lower carbon fiber costs, making it more accessible for various applications beyond sport and leisure products, such as submarine construction. China’s development of eco-friendly carbon fiber technology for underwater drones represents a significant advancement with potential implications for national defense and technological leadership in maritime environments
The new project challenges the assumption that carbon fiber doesn’t work underwater, potentially giving China an advantage in the South China Sea and Taiwan Strait. In the South China Sea, China has increased its military assertiveness towards the Philippines, while also offering diplomatic engagement. This strategy aims to strengthen Beijing’s regional influence while reducing the risk of direct conflict, particularly involving the United States.
Tensions in the Taiwan Strait have historically driven China’s military modernization efforts and strategic adjustments, focusing currently on area denial and anti-access strategies, including naval blockades. A collision near Kinmen in the Taiwan Strait in February 2024 sparked renewed tensions between Beijing and Taipei.
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