Not just a flight of fancy
For Leonardo Da Vinci, flying like a bird was simply a dream. Thanks to Deakin researchers, aircraft could be about to reach a whole new level of aeronautical sophistication, with wings that shift seamlessly to catch the updraft, minimise turbulence and give new meaning to the word “aerodynamic.”
As part of her PhD, Sahar Naghashian has spent the past four years at Deakin’s Institute for Frontier Materials (IFM) working towards achieving this.
Her work has involved harnessing the latest technology to develop shape memory, alloy-based carbon fibre composite parts that are light, strong and can change shape without any moving parts like motors, flaps, hydraulics or any of “that old-fashioned stuff.”
“We can make carbon composites change their shape by embedding metallic ‘shape memory’ wires within the composite,” said Ms Naghashian.
“These actuators have been ‘memory trained’ so they ‘remember’ their original configuration. The actuators enable the composite part to change shape through heating and cooling, which can be used to create adaptive wings.”
The ability of an alloy to remember shape was first discovered in 1963, with the development of the NiTi shape memory alloy, which is made from 50:50 nickel and titanium. This material is capable of remembering its original shape after it has been heated – unless it is subjected to extreme distortion or extreme temperature (around 400°C).
“The idea of embedding shape memory actuators within composite parts has also been around for a few decades,” explained Ms Naghashian.
“But we have been the first to map out the capability limits for these materials and thereby pave the way for virtual computer-aided design of real parts.”
“Achieving aircraft with shape morphing wings is a holy grail for aeronautical engineers,” said Ms Naghashian’s supervisor, Professor Matthew Barnett, ARC Future Fellow and Chair in Metallurgy at the IFM, “and it just might be our material that makes it possible.”
The required shape change can be achieved through gentle resistance heating of the wire within the material. This would be managed by a central control system, with specific temperatures allowing a range of positions to be achieved.
Professor Barnett explained that the technology could also potentially be used in any vehicle or object that needs aerodynamic or hydraulic control.
Potential applications could span industries as diverse as automotive, aeronautical, robotic, construction or biomedical areas.
“Memory actuating technology is now being used in the automotive industry, with General Motors, for instance, having created air vents for their smart car that can be set to different angles, depending on driving conditions,” said Professor Barnett.
“For our research, Sahar has mapped out and modelled the behaviour of the material with an ‘actuation map’. Using mathematical equations, we canpredict outcomes for specific types of composites, at specific stiffnesses and thicknesses, that will allow us to optimise outcomes.”
The Deakin research has recently been published in the international journal “Smart Materials and Structures.” It was co-authored by Ms Naghashian and her two supervisors, Professor Barnett and Associate Professor Bronwyn Fox, Research Director at Carbon Nexus.
Ms Naghashian and her supervisors are enthusiastic about the benefits of smart materials, including improved efficiency and resultant fuel savings, and noise reduction.
“There are less moving parts, so less things can go wrong. There is simpler design, with hydraulics being replaced by light, simple, smart materials,” said Professor Barnett.
After making the move from Iran to study at Deakin, Ms Naghashian is set to complete her PhD this month and is hoping to continue her research, either through a grant or industry support.
“It is very exciting to work in an area where you can see the amazing possibilities - and feel you are making a contribution,” she said.