The 4 benefits of composite armour

Andrew Elwell
Posted: 12/07/2014

1. Ballistic performance

Composite materials such as polyethylene (UHMWPE), aramid (Kevlar being one brand), fibreglass, S2-glass and carbon fibre are lighter in mass than their metallic alternatives per sq/m. That is fact. But they are invariably more mass efficient when defeating ballistic threats too.

Take the following, for example: for a polyethylene composite to stop a 7.62mm NATO round you would need a panel that weighs less than 20 kg/m2. For a slab of armoured steel to achieve the same result you need to more than double that weight.

Ceramics can also provide superior ballistic protection at a significant weight-saving over conventional armour. However, a significant problem with using ceramics in a composite solution has always bee one of adhesion and creating a system that is robust enough to withstand multiple burst-fire hits. The surface of ceramic materials is incredibly smooth; for ceramic ornaments or medical components (where the material is used to make hip joints for example) this is an essential property – for armour it is the opposite as it means nothing sticks to it. If there is no friction on the surface then adhesives have nothing to grab hold of and stick to.

Ensuring a strong bond between ceramic armour and any other surface is like trying to stick two strips of Velcro loops together (or two strips of Velcro hooks, the analogy works either way). Recently, the team at Lockheed Martin proposed a solution to the adhesion issue, which if accurate would go a long way to improving the reliability and longevity of ceramic armour systems on operations.

2. Safety beyond armour

Composites can be used for a variety of applications in the military, not just for armour protection. The safety, environmental and performance benefits of advanced high-tech fibre materials are also important when considering composites.

Last year, a Boeing 747 crashed in Afghanistan when the net constraints holding the cargo in place broke free, causing the plane to stall due to an the unbalanced weight distribution. Similar accidents have happened before on civilian – and likely military – aircraft. Had the net been made of a high molecular fabric, such as polyethylene (UHMWPE), it is probable that the accident would have been have prevented. The crash in Afghanistan resulted in the death of all seven crew members.

3. Innovative design aiding performance

The blast-resistant performance of hulls and the vehicle chassis has accelerated over the last decade after operations in Iraq and Afghanistan required engineers to come up with more intelligent, robust designs. The evolution of the V-shaped monocoque hull in particular has allowed for more composite materials to be used in a domain once exclusively reserved for hard-wearing steel.

The UK has already mass produced an armoured vehicle with an innovative composite hull design – the Foxhound. Rather than using the metal, a combination of advanced, lightweight composites were used to provide structural integrity, protection and lightweight performance. The composite pod has a V-shaped hull to help deflect the blast wave in the event of an IED explosion. The UK MoD has high hopes for the export potential of Foxhound, indicating that composite and, presumably, singlepiece hull designs are both achievable and desirable.

Other vehicles, such as Supacat’s SPV400, also have ‘pods’ manufactured with a composite moulding.

4. Lightweight capabilities

Steel has a greater mass efficiency than composites at the higher threat levels, particularly when encountering armoured piercing ammunition, but for small arms weapons – and light armoured vehicles – composites offer superior lightweight qualities.

It’s not just improved ballistic performance though; lightweight materials mean more fuel efficient vehicles, leading to cost savings. They mean more mobile and agile vehicles, which allow the military to avoid ballistic threats rather than having to protect against them. Lightweight materials mean more operational hours and less maintenance because they do not rust. They mean more flexibility and they mean greater payloads.

More weapons and personnel can be transported in theatre, increasing productivity and efficiency. Through-life costs should also be lower than with metal equivalents due to the absence of rusting and, to a lesser extent, wear and tear.

"We just cannot keep on adding tons and tons onto already heavy tanks," said Brigadier General C.P. Mohanty, North Kivu Brigade Commander, MONUSCO Mission to the DRC, United Nations.

"This is why we need to go in for composite armour, reactive armour, or whatever we can have to offset this."

But lightweight materials also mean more money. Cost is the offset. While composites are not prohibitively expensive, they are certainly more of an investment than steel and, to a lesser degree, aluminium. But that is exactly what they are: an investment. For all of the reasons stated above, composites offer a significant performance boost compared with traditional armour materials and help military forces – as well as government procurement agencies – meet their requirements. The cost savings on fuel and maintenance also provides a counterpoint to the initial outlay.

Andrew Elwell
Posted: 12/07/2014

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