My name is Adriaan Beukers, and I’m from Delft University, where I'm responsible for the research and development of lightweight structures for the aerospace department. My presentation deals with lightweight materials, the morphology of materials and structures.

The reason why we want to create lighter structures is very simple: some problems are looming. There is now a rapid decline in new oil discoveries, particularly in easy-to-reach wells; and, of course, there is a continuing increase in our consumption of fossil energy. In a few years, the price of oil will rise rapidly, especially if Chinese people like to drive cars as much as we do.

Another problem is that by burning fossil energy, we are creating the greenhouse effect. We have to be careful with the use of fossil energy.

The metaphor I’m always using is food – I’m quite jealous of people designing for food manufacturing. Here is some typical modern food: bread, meringues, chocolate bars, and the ever-popular chips or fries. These are fantastic creations – minimum material with maximum performance, in this case giving people taste, texture and a feeling of having eaten. So this is a perfect metaphor for how to create the structures of the future: minimum material use, maximum performance, maximum satisfaction.

Whether exploring remoter parts of the Earth or leaving our planet to explore space, what’s important when we go into hostile environments is that we carry along our tropical climate. We are raised in a tropical environment, and to keep yourself alive in a less friendly environment, you need cloth.

Textile structures were invented long ago, because when people first left tropical Africa to conquer all the parts of the world, it was necessary to carry along the tropical environment. Therefore they needed cloth, first skins and later manmade fibre fabrics, which kept the tropical climate next to the skin – a portable climate.

Once people start to settle, they have to find their minerals, water, and even energy, very nearby. This slide shows that travelling time all over the world, not only in poor African villages, but also in the rich North American cities, is almost equal. Everywhere, people spend one to one-and-a-half hours travelling a day. The remaining daylight time is necessary to earn money, or grow food.

Another tendency, is for people to tend to travel more kilometres a year when their income rises. So all over the world, in the richest countries, people start travelling more kilometres. The result is simple, that in poor countries there is still a tendency to use low-velocity trains, but the tendency is declining and being replaced by buses. And in Western countries, for example, the relative use of cars is diminishing, and cars are being replaced by high-velocity transport. The reason is simple: traffic jams blocking the roads mean that travelling by car is not very attractive anymore.

This graph shows resistance per unit weight. The lower the resistance per unit weight, the more effective the transport is. And what it shows for example is that the very fashionable airships they tried to introduce in the market again are very inefficient, especially the small ones. They have to overcome a lot of drag for each kilogram of load.

Buses and high-velocity trains are in fact quite efficient means of transport, and if you want to travel intercontinental, or very fast, then normal (civil) airplanes are not really a bad solution. The fact that even resistance is declining is because an aircraft is always looking for the height, the altitude, where resistance is lower, that’s why the resistance is even declining. And of course, Concorde is quite an inefficient, costly way of transport, but if we compare it with just cars, then it is still an efficient type of transport. So if you drive a Porsche at 200 kph, it has to overcome more resistance per unit weight than any other means of travelling.

So, in the very near future, we are going to have to re-use the weight of cars. And that means that we have to re-educate people, because here is a graph which shows that the more expensive the car is, the more people pay for weight. And in fact with all other modern products – your portable phone, your laptop – people pay for less weight. So it’s very unusual that people pay for heavier structures. And the reason is that people believe that the heavier structure in transport is safer and more durable.

Therefore we have to change, and for example a six-seater aircraft (1200 kg empty weight), made out of a textile structure, performs far better than a Porsche. It carries more people at one time, and its range is 2100 km and its speed is about 400 km per hour.

But of course, for short trips, we need cars, and I think one of the most important things is that we make cars not only lighter, but also smarter. If you make the car smart, so it takes over when the driver is not driving properly, then you can reduce a lot of weight, because you do not need the safety measures anymore. So, if you reduce the size and weight of the car, we can even optimise, or make use of the infrastructure we have nowadays. So cars are only attractive if we keep the speed law.

Of course, the most important developments have to be made in railway infrastructures. Take this Japanese example: in Tokyo, you never have to travel more than 10 minutes to reach a station, and once at the station, a train arrives within five minutes – a very efficient, very dense type of transport. That’s an example of a high-velocity train and, properly designed, resistance versus weight is quite attractive as well.

Wheeled transport has existed since about 4000 BC in areas where it was practical – the plains or delta areas, generally in agricultural societies. This is an example of a wheeled toy from a mountainous Aztec area where they had wheels, but didn't use them for transport because they weren't practical.

The first lightweight chariots were used in Mesopotamia and Egypt, about 4,000 years ago. This type of structure is really the lightest we can achieve. They used laminated structures, in this case, wood as a core material, and horn, which is a very good material in compression. And tendon, that’s the connection between bone and muscles, was used in the tension side of a beam loaded in bending. These types of materials were developed 3,000 to 4,000 years ago and applied for example in lightweight chariots in Egypt, here you have those chariot laminated structures, bonded, using adhesive, to create the total structure. And the woods they used were bent and cured above heat steam or smoke. In fact, the chariot's material and technology is equal to the bentwood chairs made by Thonet, except Thonet claims to have invented this technology 150 years ago, when it had already existed for 5,000 years.

The same structure was used by Lillienthal, the first man to take flight for a few minutes, with laminated wood, used with a dense silk skin – just 100 years ago, that was the standard used for flying.

Thirty years later, in the 1930s, Fokker was the biggest supplier of civil aircraft, until young entrepreneurs from the United States came up and created a new technology paradigm for the next 60 years.

Now, once again, we have a new paradigm coming up, and in fact the former textile structure will come back in new aircraft. The difference with the Lillienthal aircraft is that the textile here is frozen, by impregnating it with a resin – if you cure it, it hardens and can only sustain tension, but if you freeze it like this, then it can sustain compression as well.

This shape is typical for aircraft now under development. No tail section any more. Stability is created not by the tail, but by computers – in fact, if the computer is not working, then this aircraft is very unstable; it’s like a seed, just whirling down to the ground. Very uncontrollable, so thanks to computers, we can fly this type of aircraft.



This type of aircraft has an efficiency improvement of about 30 per cent. The resistance will decline another 30 per cent, and we feel that even the structural weight can be reduced by another 30 per cent. It’s striking that there is a big similarity with the ray fish; they have almost the same cross-sectional shape as these modern blended-wing aircraft bodies.

Buses are part of the transition, and today's metal structures will also change into frozen textile composite structures. This new example weighs only 900 kilograms, and when full it becomes quite an efficient mode of transport with respect to resistance per unit weight.

One of the ways we are creating lightweight materials is in changing from heavy materials to materials based on the lightest elements, atoms, we have. And it is important that we create a new morphology, a new shape. The lightest elements we have are hydrogen, nitrogen, oxygen and carbon (compared to the metals, iron and aluminium), and by composing those elements in one way or another, we create all our modern polymeric materials and polymeric fibres.

Fibres are very attractive, but we also have to learn something else, that the morphology of the structure can be optimized. Just by reshaping a load-carrying beam, we can reduce the quantity of material used by 80 per cent. So all new structures will have this cellular appearance.

Another possibility is that we reshape our truss structures. Nowadays, that’s the most normal way of constructing cranes, bridges and so on. By reshaping the bars, the tangent and compression bars, by optimization (as was done 100 years ago, by Michel), by reshaping, you can reduce the quantity of material and so the weight, by 60 per cent.

Structure: that’s what it’s all about. This is wood, and wood consists of cellulose fibres. In nature, we have a lot of fibrous materials, and the fibres become attractive if we bundle them, twist them and make tows out of it. Again, this has been done for thousands of years already, by using a distaff effect, a wheel and an axle.

Nowadays, we produce these materials from glass, quite a heavy solution. But also by pyrolising, carbonization of synthetic fibres. Once you have the fibre, you can create all kinds of structures. All the techniques are very old as well.

If we start to create structures, we have to deal with the loading conditions, and one of the simplest loading conditions is tension, like a spider's web. Two principal structures are shown, the chain and the stay. Bridges, for example, the lightest bridges we have are based on this chain principal. For example, the Golden Gate Bridge, constructed 60 years ago, is a kind of textile technology: big bundles of steel wires are woven from one side to the other.



But a problem here is maintenance – they need 20,000 kg of paint each year to keep this bridge working. Well, if we change from steel to carbon fibre, we can create a span, which is four times bigger than the Golden Gate Bridge. The maximum in steel nowadays is 1,500 to 2,000 metres; in carbon fibre, we can create spans of 10 kilometres, so we can span the Straits of Messina and Gibraltar by using carbon fibres only.

Another possibility is that we create using fibrous textiles, and this is a typical structure loaded in tension, and the tension in balance with those beams which are loaded in compression. If we replace the compression bars by air, by gasses under pressure, we can create inflatable structures which are the lightest solutions for all kinds of structures.
And I shall show you a few of them.
Here in the 1950s, a salaryman’s dream in the United States was an inflatable aircraft. Minimum volume. And Saturday you start to pump it up. Well, it was quite a lot of work, but once inflated, you could fly it. Of course, the materials and design are state-of-the-art 1950s and not really efficient.

Nowadays, people are starting to use those inflatable, flexible structures again, and in Switzerland they designed this ray-type of aircraft. Another example is in space; they use inflatables for antennas. And people are even thinking about satellites, inflatable satellites floating around the Earth.

Inflatable structures, such as the Hindenburg airship, could be of huge size. By the way, the Hindenburg was quite efficient on the count of resistance versus weight, because of its length. So the bigger you make these types of structures, the more efficient they become, but the problem is that they are too slow and too costly. In the Thirties, the gas they used – hydrogen – was very dangerous. And I feel that these types of floating structures, balloon structures, are only attractive for heavy load lifting.

For building, they are attractive as well: create the textile structure, and once you inflate it, you have a structure which is light and easily placeable.

It is very important that we rethink packaging today. Here we have a flexible structure, the goatskin – used to transport water, or milk, or even to make butter.

Beer kegs are very heavy. These metal kegs are wood mimics; they are similar to wooden barrels. This is what people always do when there’s a new material – they start to imitate the old designs in the new material. So what we did was redesign the beer keg, and what’s shown here is an inflatable structure. It only weighs one kilogram, and beer is squeezed in and out by pressurisation. In Holland, we squeeze the beer out of the keg by adding carbon dioxide, so you have to transport carbon dioxide to get your beer. Here it’s not necessary. Well, this beer keg was developed by two students and will be produced next year in a new factory. It will replace aluminium kegs for export beers. It is a typical example of very old technologies and materials, updated in a new modern, synthetic version.

Here is another means of transport: gas. In large parts of the world, people cook using gas. And in China, girls transport natural gas by just using thin polypropylene tubes. They use it in agriculture. And they have stolen the gas from the pipelines. So it's cheap and easy, and very efficient.



Of course, we cannot transport gas at atmospheric pressure, because then you need a big volume. But if you increase the pressure, you can diminish the volume. So two other students developed a structure, once again based on textile principles. It can store 65 litres of gas in a container which weighs only nine kg. The funny thing is that, when tested, it did not explode like a metal container, but just lost it’s fit at the crown of the structure. So if you compare it to steel versions, it’s not only the weight reduction that’s important, but also the safety. If you have a fire or a build-up of pressure, the new, carbon fibre one will not explode.This shows that, if you have a good design, even using more expensive materials, you can create structures which are higher performance (and therefore cheaper) than the traditional steel versions.

To conclude, if we become as lazy as bees and as efficient as bees we can create structures which perform much better than those we have now. And like the bees, we can create them with minimum material and, of course, minimum energy.