Introducing nanotechnology to shipbuilding

 Originally posted on Motorship

http://www.motorship.com/comment-and-analysis101/introducing-nanotechnology-to-shipbuilding

Naval architect M. Rajeev of Axsys Technologies in India has contacted The Motorship with his ideas about nanotechnology in shipbuilding, a subject he says has fascinated him throughout his career.

Why not, Rajeev asks, consider a material other than steel for construction of ships when the material is lightweight, hence lower fuel consumption, as well as providing reduced corrosion, and efficiency? As with any other material, there will be a negative side too.

Rajeev proposes a reinforced plastic/aluminium material with carbon nanotubes so as to achieve qualities equivalent to steel or higher. Research into nanotubes/composites has revealed the following properties: 

Mechanical strength: high modulus of elasticity and excellent tensile strength which is five times higher than that of steel – at only a quarter of the specific weight.

Electrical conductivity: electrical conductivity comparable to that of copper, allowing non-conductive plastics to be transformed into conductive materials.

Thermal conductivity: matches thermal conductivity of diamond -the best natural thermal conductor of all.

The questions arising are, first of all, cost. Although the relative strengths mean that an 8mm thickness of carbon nanotube material would be equivalent to 20mm steel, how would the cost compare? Then, welding steel is cheap and simple. How would joining nano composite plates compare? The whole ship is not made of steel – can carbon nanotubes be attached to other . shipbuilding materials, such as aluminum, or would the whole ship have to be built using composites?. 

Although carbon nanotubes display good tensile strength, how does fatigue life compare? And what about the end-of-life implications? Can nanotubes be recycled, like steel?.

Rajeev is seeking feedback from the industry to help answer these, and other, points, including:

1. Define the actual material to be used;
2. Identify a source of high-quality carbon nano tube material in sufficient quantities;
3. Establish properties through lab tests;
4. Determine how to join stiffeners/plates – is moulding/casting the best option?
5. Study bending, buckling, impact resistance, and fatigue of large reinforced panels under various loads:
6. Determine fire, wear, tear and saline atmospheric effects through practical tests; and
7. Model tests.

Then Rajeev suggests consideration of the following to establish the feasibility of nanotubes in shipbuilding:

1. Availability of skilled labour for construction:
2. Construction effectives, economic viability (cost/ton)
3. Repairability
4. In service maintenance
5. Recyclability and its costs