In the 1986 movie Star Trek 4: The Voyage Home, Chief Engineer Montgomery Scott went back in time, along with the rest of the Enterprise crew to capture a pair of humpback whales in order to save humanity from an alien space probe. To do so, Scott offered the formula for “transparent aluminum” in exchange for the huge plates of plexiglas needed to contain the whales on board his ship.
Fast forward 30 years and transparent aluminum-containing material now exists and is currently being developed by Surmet Corporation.
It is called Aluminium oxynitride or AlON, and classification society DNV GL says it represents a promising development in lightweight materials for certain applications. “AION is a transparent polycrystalline ceramic that is optically transparent and about three times harder than steel of the same thickness. The material remains solid up to 1200°C, and has good resistance to corrosion and damage from radiation and oxidation.” Typical applications are domes, tubes, transparent windows, rods and plates, according to Surmet Corp.
There are certainly thousands of possible applications of this material, most of which are cost-prohibitive at the moment within the shipping industry, but as efficient methods of production are developed, DNV GL sees future applications of AlON in cruise ships, for example, which may have large structures made of transparent alumina to provide passengers with better views while staying in compliance with strength integrity regulations.
DNV GL invests upwards of five percent of their company’s yearly turnover into research and development, and this is one of the many areas the company is looking into.
Another incredible material under consideration is graphene.
Made up of one-atom thick layers of carbon, a single sheet of graphene is the thinnest material ever observed and is up to 200 times stronger than common steel. A study by Recep Zan, Quentin M. Ramasse, Ursel Bangert, Konstantin S. Novoselov at Cornell University has found that it is also self-healing and so impermeable that not even helium atoms can pass through it.
DNV GL notes that graphene is flexible, light, nearly transparent and an excellent conductor of heat and electricity. “As it is both stronger and stiffer than any known material, it could be used to manufacture products and structures that would be a fraction of the weight and stronger than anything produced today,” says DNV GL. “Graphene could also be used to strengthen polymer or metal composites.”
Steel is, and will continue to be, the material of choice in the shipbuilding world due to it’s availability and industry’s understanding of it as construction material. As these new technologies evolve and gain traction in other industries, DNV GL says that commercial pressures will begin to allow it to gain a foothold in the shipbuilding world.
“AlON, graphene, and similar lightweight materials merit further consideration in many shipboard applications. However, improvements in steel microstructure and the use of novel manufacturing technologies will also introduce many opportunities for innovation,” says Narasi Sridhar, Director for the Materials Program in DNV GL Strategic Research & Innovation unit
3-D Woven Fabrics
DNV GL notes that not only will new materials be implemented in the future, but existing materials will be used in ways that were never possible before.
“Until recently, the increasing application of composites to make structures lighter and more corrosion-resistant has been slowed by the inefficient manual joining processes used today,” says DNV GL. “Improving the reliability and efficiency of composite joining processes requires replacing traditional hand-lay-up processes with new 3D weaving technologies. The new approach to joining structures significantly simplifies the complexity of parts and reduces the number of components used, dramatically improving the viability of composite lightweight solutions.”
Steel can be modified in a number of ways to change its properties. This includes adding more or less carbon to the steel, varying the duration of the cooling period of the steel and forging it. None of these processes change the density of the material in a significant way however, they just make the steel more or less susceptible to fracture, corrosion, or fatigue.
Turning that same bit of material into a steel piece of what might be considered pumice was not possible, until now.
DNV GL says metal foam can dramatically improve the weight-to-stiffness ratio and energy dissipation of a steel structure. It will also have a positive effect on a vessel’s vibration, thermal, and acoustic performance. Properly constructed, foamed components can have higher bending stiffness and weigh less than solid steel. A sandwich panel with steel faces of one millimetre with a 14 mm metal foam core has a comparable bending stiffness of a 10 mm solid steel plate, at merely 35 percent of the weight, says DNV GL.
Imagine a ship with self-healing skin, capable of continuously adjusting to changing sea and wind conditions, one that can generate its own energy and is equipped with embedded sensors that can provide real-time information to the bridge and shore-based facilities.
DNV GL defines self-healing materials by their ability to detect, heal and repair damage automatically. Different types of materials, such as plastics, polymers, paints, coatings, metals, alloys, ceramics and concrete have their own self-healing mechanisms. Some materials may include healing agents, which are released into the crack-plane through capillary action. When a crack ruptures the embedded microcapsules, a polymerization process is triggered, bonding the crack faces. This technology can be utilized on any surface on a ship, including tanks and hard-to-reach structural areas.
Intelligent materials could incorporate functional ingredients such as nano- particles, micro-electromechanical systems (MEMS) and Radio-Frequency Identification (RFIDs), among others. These technologies enable self-repair, self- healing and sensing. In the future, smart coatings may incorporate pH sensitive microcapsules for corrosion monitoring and deliver corrosion inhibitors. Likewise, work to develop and produce “smart dust” – a network of microscopic wireless MEMS sensors – may provide a whole range of benefits to the shipping industry.
“There are many opportunities to apply smart, low drag coating technologies developed in other industries, such as biomedical and oil and gas, to shipping,” says Sridhar.
In our lifetimes, the implementation of composite structures and carbon nanotubes into the commercial shipping industry could enable an entire ship’s structure to function in-part as a huge capacitor powered by printable photovoltaic cells on the ship’s exterior.
Computer Aided Material Innovation
A newly emerging trend that promises to accelerate the innovation and application of new materials is integrated computational materials engineering (ICME). ICME leverages the power of advanced modeling and simulation, verified and validated against experimental testing, to strategically target the optimal materials design space, thus reducing the amount of “trial and error” required at the lab bench. An example of the successful ICME approach was the design of high strength “cybersteels” by the US DoD in collaboration with Northwestern University and Questek to produce qualified materials designs for landing gears with significant cost and time reductions.
”The ability to design and manufacture structures from the atom up will bring important capabilities to tailor form and function to a specific application,” says Christopher Taylor, Senior Researcher in the Materials Program at DNV GL SR&I.
There’s no doubt that many of these technologies will take some time to filter into the maritime and offshore industry, but it hopefully provides a glimpse into what could be an extraordinary step-change in naval architecture over the next few decades.