Next generation protection

Tuesday, June 29, 2010

DMJ's Anthony Hall speaks to Professor Bryn James, from the Defence Science and Technology Laboratory, about the development of new types of armour…

Increasingly high levels of scientific innovation are being applied to the age old problem of mobility versus combat survivability. Professor Bryn James, head of the armour and protection science centre at the Defence Science and Technology Laboratory (Dstl), says its remit is a broad one: "What the group does is research into physical protection for all applications including ground, sea, air, and fortified buildings. What we want to do is make armour better, as in lighter, thinner, cheaper, so it is more useable."

The creation of new armours for vehicles, continues James, creates particular challenges, posed by their defining characteristic. "Compared to all the other applications, they move, and the basic physics of that means they have to be reasonably light. Now we could put the very, very best protection on, but then it would weigh 200 tonnes; it wouldn't be able to move and would be tactically useless."

The weight versus mobility issue is leading research teams into areas of material science as a way to solve the paradox, reveals James: "We are very, very interested in materials, and are looking at pretty much everything that is available." What researchers are striving for, he explains, is for materials to be made stronger but with the same weight, which will save load on the vehicle. Materials are also being developed to provide enhanced protection levels, and these include self-healing materials, a concept that employs both solid and fluid characteristics, as the Professor explains: "If you try to move the surface of these materials very, very quickly, as in impact, they won't want to move and will present a really strong material to the penetrator," he says. "But once they have been penetrated, there is creep in the material that will allow gaps to be filled in." This ability to self-repair sounds remarkable, but James introduces a note of caution: "I have to say it is slightly disappointing. These materials are not magic. There is nothing perfect that not only stops the bullet but then self-heals – that doesn't exist. We'd love it to but it just doesn't happen."

The creation of armour that reacts to penetration is also the objective of a piece of research that is utilising an innovative form of protective capability. "We are working in the field of electric armour," he explains. "This is essentially where you have two parallel plates arranged so that when an RPG strikes, the resulting jet of copper from the warhead penetrates the first plate, and makes an electric connection as it hits the second plate. You can arrange it so that a current can flow towards the first plate and blow the jet apart. So instead of penetrating the vehicle, the RPG jet becomes a cloud of copper dust, which dissipates." The system has been demonstrated, he says, "and we are working on that at the moment."

Another promising area of research is concerned with the creation and uses of metals. "We are looking at relatively new alloys using all the materials you would expect: aluminium, steel, titanium, but we are looking at subtle changes in the content. We have shown recently that by changing the alloy content of old-fashioned type materials, like steel, we can actually make it better in impact." James believes that altering the composition of traditional materials is creating substantial improvements. "Steel is not ultra modern, but there are things you can do to it to make it cheaper to produce, better in performance, and easier to work."

Producing materials that are easier to fabricate and build vehicles from, James insists, is an important quality in armour which should not be underestimated. "That is a real issue because we've got some older materials that are hard to weld and difficult to join – but if we can make a material like superbainitic steel (Super Bainite), which is as good as armour steel but significantly easier and cheaper to make and easier to fabricate once it's made – then these are all good things and make a great deal of difference." It is the importance of meeting production requirements, notes the Professor, that most people miss. "We could come up with the best armour ever, but if it costs a million pounds to put it on a vehicle, it's not going there. It has got to be cost-effective."

Together with alloys, and what James refers to as the more traditional metals, work on composites is also producing positive results. "Composites are generally a glass fibre or carbon fibre composite with polymer or just the polymer itself," he tells us. "We use composite materials, and we use polymers to great effect because their strength to weight ratio is very good, and they have very attractive properties. We are using them more and more and if they're used in the right place as part of the armour system, they can be very valuable, but you have to know what you're doing to put them in the right place."

Once fabricated, armour systems can also be provided with extra defensive capabilities by the application of chemical coatings, Professor James continues. "They are very thin, and have negligible effect on impact performance," he says, "but they can have considerable usefulness in improving camouflage, concealment and stealth. Coatings can make you less visible in all areas of the spectrum – so that's in the optical spectrum, the radio frequency spectrum, the radar spectrum, and in the infrared and ultraviolet."

Coatings also have the ability to help protect vehicles against chemical threats. "You can put on coatings that are really easy to remove," says James. "So if a vehicle is in danger of being sprayed with something toxic, you can put coatings on the surface that act as a protective removable layer. If you are covered with anything nasty, the coating can be peeled off, taking the nasty with it, instead of having to clean the vehicle off."