New technique paves the way for 3D-printed aircraft wings

Source: BAE Systems Advanced Technology Centre

Aircraft wings built with 3D printers could be a step closer thanks to a technique developed by BAE Systems.

The company has developed a process to prevent large metallic structures made using additive manufacturing from distorting or building up internal stress during printing, potentially paving the way for making components strong enough to use in aircraft.

The technique involves an established way of making metal parts stronger by rapidly and repeatedly striking them using an ultrasonic tool – a form of peening – applied as each layer of the component is laid down by the 3D printer in order to relieve stresses and improve the material’s microstructure.

Civil aircraft manufacturers including Boeing and Airbus are already using 3D printing to produce small components such as hinges as a way of reducing waste of expensive materials such as titanium.

Scaling up the process to large and complex metallic parts could also the enable the creation of more complex shapes – for example hollow and therefore lighter wings – and make production of a small number of these components more cost effective.

But increasing the size of 3D printed parts raises the chance that the internal stresses that build up as the material cools will lead to problems, said Andy Wescott, a senior research scientist at BAE’s Advanced Technology Centre.

‘As the material contracts it creates residual stress that is locked into the part,’ he told The Engineer. ‘This can manifest as distortion but also affects the mechanical performance.’

With BAE’s technique, a layer of material is laid down, melted into shape using a laser and left to cool before being cold worked using the ultrasonic impact treatment (UIT). The next layer is then deposited, heated and the process starts again.

‘It’s not just the cold working step that produces the positive result,’ said Jagjit Sidu, the ATC’s technical leader for additive manufacturing. ‘It’s the combination of the cold working with the heat treatment. It all becomes part of the deposition process.’

Source: BAE Systems Advanced Technology Centre

A comparison of the microstructure of 3D-printed parts made with and without the treatment.

UIT is typically used to treat welded areas in metallic structures in the rail and oil and gas industries to increase their fatigue life.

An ultrasonic transducer causes the tool head to vibrate at a very controllable rate and impart powerful compression forces while only placing a small load on the tool itself, allowing it to be handheld – or in this case fitted to a robot, meaning it could be easily integrated with additive manufacturing systems.

The BAE team, which also included group leader for materials engineering Stephen Morgan, developed a feedback system that uses load cells in the base plate, onto which the structure is printed, to measure the strains as they form and adjust the UIT to correct them in real time.

Asked how much time the treatment added to the 3D printing process, Westcott declined to give a specific figure but said: ‘It is a quick manual or automated process. From the measurements obtained from our strain measuring system, the surface quickly becomes saturated and no further amount of treatment has any effect.

‘Obviously, if you treat every layer it is a longer process than if you treat every five layers, but optimising the process will be the subject of further work.’

The company has demonstrated the technique by producing 3D printed structures up to 1m in length and has applied for patents on the UIT process and the feedback system.

Now the researchers plan to further optimise the process and build a better understanding of where to apply the UIT in larger and more complex parts, in order to be able to move towards prototype components.

This article first appeared on The Engineer.

Putting our faith in a fracking dream is a dangerous mistake

Perhaps it’s the sunshine, but I desperately wanted to write about a new sense of optimism in UK industry this morning. We may be a long way from true recovery but positive economic statistics, billions of pounds of foreign investment, new infrastructure development and a renewed focus on industrial research give us real reasons to be positive about the future.

The Olympics may or may not have created a £10bn boost to the economy but it appeared to represent a mental turning point. As I was reminded at this week’s Royal Academy of Engineering Awards, British engineering has a lot to be proud of and we are now far more confident in showing it off to the world.

But my mood has been sadly disrupted by news that George Osborne is ramping up his “dash for gas” and plans to halve the tax bill for fossil fuel companies who start fracking the English countryside. The promise of a glut of cheap gas that brings down the heating bills of hard-pressed families and helps cut the UK’s carbon emissions by displacing coal – and creates thousands of jobs at the same time – is an attractive one.

But extraordinary claims require extraordinary evidence and, so far, evidence is severely lacking. Yes, we’ve seen the reports that Britain may be sitting on top of trillions of cubic metres of shale gas, but how much of it we can viably extract and what impact it will have on prices are still big unknowns.

A recent inquiry by industry and academic experts led by a former Tory energy minister and a Labour peer was the latest to conclude that the amount of economically recoverably shale gas in the UK remained highly uncertain, the environmental risks were poorly understood, and the near-term impact of fracking would be to diversify Britain’s energy exports rather than significantly lower prices.

The US may be reaping the benefits of its own shale gas revolution but the UK is a very different place. Instead of wide-open and sparsely populated plains that can be industrialised with little opposition, we have a crowded island where green countryside is preciously guarded and environmental damage would be more keenly felt.

The £100,000 per well that Osborne is offering to communities that host fracking sites won’t go far in an era of massive public spending cuts and seems small fry compared to the tax cuts (from 62 per cent to 30 per cent) being offered to an already wealthy industry that could make billions more. How easily will fracking operations be set up in the Tory shires that display such opposition to windmills?

We also have tighter regulations making operations more costly and an energy market that is tied more closely with that of our neighbours. As the Carbon Connect report put it: ‘Our liberalised and highly interconnected market would prevent prices remaining artificially low compared with neighbouring markets.’

With so many uncertain factors, it would be immensely foolish to tie ourselves to a strategy of more gas-fired power stations when we have a once-in-a-generation opportunity to move away from a reliance on fossil fuels. If the shale gas dreams turn out to be nothing more than hallucinations, we’ll be left at the mercy of an international market struggling with ever-increasing demand from rapidly developing countries.

Then, of course, come the environmental issues. Fears about earthquakes are a red herring – research has found fracking represents a similar a threat in this sense to coal mining and that resulting tremors would unlikely be felt at the surface. But what of the chemicals pumped into the ground and their impact on the water supply? Water firms have this week warned again of the dangers fracking pose both from its chemicals and its high water usage.

The Environment Agency says companies will only be allowed to use non-hazardous substances and the UK oil and gas industry likes to boast about its strong safety and environmental record. Behind the scenes, however, some experts are not so confident the rules will be strictly followed, and oil and chemical leaks are still common on North Sea rigs.

Perhaps most importantly of all, fracking will not reduce carbon emissions. Shale gas might help the UK meet its medium term CO2 targets but a greater supply of fossil fuels will put downwards pressure on prices and deter countries from decarbonising. We’re already seeing it happen in Europe, where coal consumption has increased thanks to a surge in US exports as the country switches to shale.

Simply put, the more fossil fuels the world takes out of the ground, the more carbon it will emit and the greater the risk of runaway climate change. There are so many uncertainties around fracking but we can be sure of one thing: it’s not the answer to the world’s climate problem.

This article first appeared on The Engineer.

Interview: Olympic bike designer Dimitris Katsanis

Composites specialist Dimitris Katsanis was one of the secrets to team GB’s cycling success at the London Olympics. 

Dimitris Katsanis

When British Cycling gave Dimitris Katsanis six months to build the best bike in the world, it was a challenge not every engineer would have risen to. But then not every bike designer has been an international competitive track sprinter. The Greek-born expert in composites had moved into the aerospace industry in the years since his professional cycling career but he had kept hisconnections with the sporting world and had been among the first to apply expertise in carbon fibre to building bikes for several national teams.

So when the UK’s governing body for cycle racing wanted to address problems with the bikes used in the 2001 racing season, Katsanis was well placed to put forward his ideas. He also benefited, he says, from the organisation’s open-mindedness and willingness to take risks. ‘One of the great advantages when British Cycling came to me was they gave me a free hand. Not “we want this, that and the other”, just “make us a frame: if it is good we’ll take it; if it is no good, forget about it”.’

Despite this freedom, Katsanis’s ideas weren’t revolutionary. They were more about addressing component quality and supply-chain reliability, making use of the ample data that British Cycling provided on the amount of power and torque the riders were producing. ‘Many people like to glamorise it but in reality it’s just common-sense engineering,’ he says. ‘It doesn’t matter if you’re designing [a bike or] an aeroplane wing: you have your loads, you have where the thing is supported, where the loads are going through. You just have to make it strong enough to do the job.’

And, he says, he took a conservative approach to the sport’s regulations, even though he suspected other teams were stretching the rules, which he claims weren’t consistently enforced at the time. ‘The worst thing that could happen would be the British cycling team getting to the starting line at the Olympic Games and then finding out they cannot race.’

The results, however, spoke for themselves. ‘Chris Hoy used it straight away,’ he remembers. ‘He broke his own record straight away by quarter of a second. A quarter of a second on the sprint is actually quite a difference.’ A 12-year partnership followed, during which, Katsanis claims, his bikes have won 51 gold medals in the World Championships and Olympic Games, including Team GB’s hauls in Beijing in 2008 and in London last year.

Though the UK has gradually risen to the top of the world’s cycling ranks, the technology in the bikes hasn’t changed that much since Katsanis’s early designs for British Cycling. Carbon fibres had been refined in other industries, most notably aerospace, so it was more a case of bringing that knowledge across into the sport than inventing something new, he explains.

‘Ten years ago the materials weren’t really that different compared with what they are today, in terms of things you can actually use… I would need to do quite a lot of testing to prove that something is actually better. Carbon nanotubes and so on are still not quite there as a structural material.’

What has changed is his and other manufacturers’ ability to work with the materials, primarily thanks to improved analysis techniques, which helped Katsanis make large strides in making the bikes more aerodynamic. ‘Twelve years ago if you were trying to do aerodynamic simulations and so on you could only do some very crude bits,’ he says. ‘Structural analysis was more common than CFD [computational fluid dynamics] but, still, it was quite cumbersome. So in fact, information technology is probably the most important factor that has sped things up quite considerably.’

However, Katsanis doesn’t like to rely completely on software and simulations — partly because they sometimes throw up anomalies that need to be manually identified and partly because he likes to stay in control of the engineering process. ‘I favour doing a number of different solutions. You look at the results, you pick the one that perhaps is the best and you run with that,’ he says. ‘A lot of people do the simulation by running hundreds of different solutions and letting the software manipulate the shapes — I’m not keen on that.’

This emphasis on keeping a firm grip on the engineering was mirrored by Katsanis’s desire to stay close to the users of his creations — the riders — rather than have their views filtered through managers and coaches. And this was where his own cycling experience came in useful too. ‘It gave me a little bit of background information that you cannot tease out from the riders,’ he explains. ‘They will give you that bit of a hint that they think is not really crucial but you realise this is something that can make a difference.’

Katsanis’s professional cycling career didn’t last long, although he did once come up against British Olympic gold-winning racer Chris Boardman, with whom he would later collaborate on one of the UK’s time-trial bikes. ‘He was one or two places ahead of me at that time; he improved a bit since,’ he laughs. But it was Katsanis’s interest in racing that eventually made him return to an earlier fascination with engineering.

After realising that his sports-science degree and a career in coaching wasn’t going to satisfy him, he thought back to his youthful exploits of taking apart motorbikes and trying to make them go faster. At the same time he had been building his own bicycles from steel tubes and looking around for the next step in bike technology. He found it in the field of composite materials, which had yet to fully emerge into the world of sports engineering, even in motor racing, and began to experiment.

‘The very first full composite structure I did was a racing wheelchair back in Greece in 1992 [for the Barcelona Paralympics],’ he says. ‘It was a full carbon chair with carbon disc wheels — very primitive but it was lighter, stiffer and more aerodynamic.’ Amazingly, this was before he had even begun to study composite engineering, which he would go on to do at Plymouth University. ‘I bought a book about composites. My English was so-so, my engineering knowledge was very basic and a lot of things were not making sense. But I used it as well as I could and it worked quite well. So when I actually went to study composites engineering I had already done some.’

Now Katsanis has come full circle, having helped design a carbon-fibre racing wheelchair for the UK that will be used at this year’s World Championships.He’s also continuing his work with UK Sport, helping in preparations for next year’s Winter Olympics — a field in which he already has some experience, having helped design parts for the British bobsleigh. He also recently contributed to the Pinarello bike Bradley Wiggins used in his unsuccessful Giro Italia attempt that Team Sky is also using for the Tour de France.

But he’s also looking at a return to aerospace and hoping to expand his own engineering company, Metron Advanced Equipment. ‘In terms of performance, all the research and development comes from aerospace — the Cold War was great for engineers,’ he jokes. ‘It has very long development times usually. In Formula One, for example, if they get a sniff that they can do something veryquickly and get a tiny percentage increase they will go for it. Whereas in aerospace they will test it again and again and document it, which actually produces a vast amount of literature for the rest of the engineers to look into.’ Perhaps going back to the sector will provide Katsanis with the fuel for the next great sports technology innovation.

This article first appeared on The Engineer.

Curriculum alone won't guarantee our future engineers

The new national curriculum announced this week was met by a mixture of cheers from those who praised its return to “rigorous standards” and jeers from those who claim it places too much emphasis on memorising a narrow selection of facts rather than understanding, in some ways the typical response we have come to expect to education measures announced by the current government.

But one area of the new study programme was met with near universal praise: design and technology. Under the new guidelines, children will be taught how to design and make products from a young age, learn how to use modern manufacturing tools such as laser cutters and 3D printers, and incorporate and program micro-processors into their creations.

This is a far cry from the previously “dumbed-down” attempt to redesign the curriculum that was scrapped earlier this year after criticisms of its focus on life skills such as bike maintenance rather than engineering-related disciplines.

After that debacle, the Department for Education turned to industry experts, including the Royal Academy of Engineering, for help drafting a new programme that would be more likely to engage children with the principles of designing and making, thereby better preparing them for an increasingly technology-dominated world and potentially for a related career.

Certainly, there is much to admire about the new D&T curriculum. Exposing children to the tools and processes that engineers use and encouraging young people to apply creativity to technology, rather than just teaching them how to press buttons, could help make engineering seem less mysterious, irrelevant or dirty and potentially lead to a greater take up of the profession. But it could also teach valuable skills that can be applied far outside designing and making: problem solving, practicality, and innovation.

However, this comes with several caveats. Firstly, the increasingly fragmented education system means that the new national curriculum won’t actually be compulsory in most secondary schools as most are now academies or free schools outside of local authority control. That doesn’t mean these schools won’t follow the guidelines anyway or do a good job developing their own, just that there’s a limit to what can be achieved with the government’s “national” curriculum.

Secondly, even the best study programme is useless without good teachers to implement it. Teachers need the correct training and support to ensure the principles laid out in the new curriculum aren’t lost in a scramble for exam results or due to lack of expertise and understanding. A 3D printer in every school could be a great thing if properly used but there is a great danger of them becoming fashionable toys or expensive doorstops. Perhaps worse would be if children started to think all goods could be made using 3D printers, further divorcing them from the realities and challenges of engineering.

With these issues in mind, industry needs to continue and expand its work engaging with schools and teachers directly to make sure all children (or as many as possible) are taught in a way that is useful to them personally and to society (including business) in general

This includes a balance between the need to equip young people with skills for future careers and enabling them to develop as individuals. It was heartening that the Royal Academy’s response to the curriculum was to praise its potential to ‘help young people interact more knowledgably with the world around them’, rather than focus on its ability to create engineers.

Schools aren’t work training centres and too often some employers appear to want young recruits to arrive with all the skills needed for specific jobs, rather than accepting the need to carry out some training themselves. But if we can inspire and educate with the right experiences then we can produce young people who are ready to mould, eager to learn, and full of new ideas.

This article first appeared on The Engineer.