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Showing posts with label North Sea. Show all posts
Showing posts with label North Sea. Show all posts

Friday, July 29, 2011

Southampton engineers fly the world's first 'printed' aircraft


Engineers at the University of Southampton have designed and flown the world's first 'printed' aircraft, which could revolutionise the economics of aircraft design.
SULSA is the world's first "printed" aircraft.
Credit: University of Southampton

The SULSA (Southampton University Laser Sintered Aircraft) plane is an unmanned air vehicle (UAV) whose entire structure has been printed, including wings, integral control surfaces and access hatches. It was printed on an EOS EOSINT P730 nylon laser sintering machine, which fabricates plastic or metal objects, building up the item layer by layer.

No fasteners were used and all equipment was attached using 'snap fit' techniques so that the entire aircraft can be put together without tools in minutes.

The electric-powered aircraft, with a 2-metres wingspan, has a top speed of nearly 100 miles per hour, but when in cruise mode is almost silent. The aircraft is also equipped with a miniature autopilot developed by Dr Matt Bennett, one of the members of the team.

Laser sintering allows the designer to create shapes and structures that would normally involve costly traditional manufacturing techniques. This technology allows a highly-tailored aircraft to be developed from concept to first flight in days. Using conventional materials and manufacturing techniques, such as composites, this would normally take months. Furthermore, because no tooling is required for manufacture, radical changes to the shape and scale of the aircraft can be made with no extra cost.

This project has been led by Professors Andy Keane and Jim Scanlan from the University's Computational Engineering and Design Research group.

Professor Scanlon says: "The flexibility of the laser sintering process allows the design team to re-visit historical techniques and ideas that would have been prohibitively expensive using conventional manufacturing. One of these ideas involves the use of a Geodetic structure. This type of structure was initially developed by Barnes Wallis and famously used on the Vickers Wellington bomber which first flew in 1936. This form of structure is very stiff and lightweight, but very complex. If it was manufactured conventionally it would require a large number of individually tailored parts that would have to be bonded or fastened at great expense."



Professor Keane adds: "Another design benefit that laser sintering provides is the use of an elliptical wing planform. Aerodynamicists have, for decades, known that elliptical wings offer drag benefits. The Spitfire wing was recognised as an extremely efficient design but it was notoriously difficult and expensive to manufacture. Again laser sintering removes the manufacturing constraint associated with shape complexity and in the SULSA aircraft there is no cost penalty in using an elliptical shape."

SULSA is part of the EPSRC-funded DECODE project, which is employing the use of leading edge manufacturing techniques, such as laser sintering, to demonstrate their use in the design of UAVs.

The University of Southampton has been at the forefront of UAV development since the early 1990s, when work began on the Autosub programme at its waterfront campus at the National Oceanography Centre, Southampton. A battery powered submarine travelled under sea ice in more than 300 voyages to map the North Sea, and assess herring stocks.

Now, the University is launching a groundbreaking course which enables students to take a Master's Degree in unmanned autonomous vehicle (UAV) design.

Provided by University of Southampton

Tuesday, July 5, 2011

Specialized seeds can really float your boat


A new artificial surface inspired by floating seeds, which could provide an alternative to the toxic paints currently used to prevent fouling on ship hulls, has been developed by German scientists.
The evolution of a seed-inspired anti-fouling coating.From extreme left: Dypsis rivularis seeds; Electron microscope image of the seed surface; Electron microscope image of the artificial surface based on the seeds; Test panel of artificial surface after 12 weeks in the North Sea, showing minimal fouling.Credit: Biomimetics-Innovation-Centre (B-I-C), University of Applied Sciences.
Scientists from the Biomimetics-Innovation-Centre have developed a new anti-fouling surface based on a seed from a species of palm tree. "These plants have seeds which are dispersed by the ocean currents. As it is an advantage for these seeds to remain free of fouling to allow them to disperse further, we guessed they might have specialised surfaces we could mimic," explains Katrin Mühlenbruch, a PhD researcher who is presenting this work at the Society for Experimental Biology Annual Conference in Glasgow on the 4th of July 2011.

The researchers floated seeds from 50 species in the North Sea for 12 weeks. The seeds of 12 species showed no fouling at all. "We then began by examining the micro-structure of the seeds' surfaces, to see if we could translate them into an artificial surface. The seeds we chose to mimic had a hairy-like structure," says Ms. Mühlenbruch. "This structure might be especially good at preventing fouling because the fibres constantly move, preventing marine organisms from finding a place to settle."

Using a silicone base the scientists created an artificial surface similar to the seeds, with fibres covering the surface. Currently the new surface is being trialled by floating it in the sea. "Initial results are quite good," says Ms. Mühlenbruch. "But we still have a long way to go"



Fouling by seaweeds and marine animals is a problem for the shipping industry, resulting in increased fuel costs. Currently the only solutions are highly toxic and environmentally damaging marine paints which are specifically designed to leach biocides to prevent organisms settling on the hull. "Our aim is to provide a new toxin-free and bio-inspired ship coating," says Ms. Mühlenbruch. "This would prevent environmental damage while allowing ships to operate efficiently."

Future work will include analysing the chemical composition of the seeds' surface, to find out whether this adds to their anti-fouling properties.