Aussie armour - Australian defence research

Materials World magazine
,
1 Mar 2010
Cross-section of a typical small arms protective insert (a ceramic-composite armour)

The need for superior armour materials and manufacturing technologies has never been so great. Ian Crouch of Australian Defence Apparel explains how the country is responding.

Ever since the infamous Australian bushranger Ned Kellycrafted his inventive but burdensome wrought steel armour in the late 19thcentury, Australian armour technologists have been looking to develop body armour that is ultra-lightweight, highly protective and extremely comfortable.

Currently the Australian Defence Force wears a modular combat body armour system, but what of the next generation? Might the US vision of a Future Force Warrior in 2032 be realised and globally adopted?

In response to this challenge, Australia’s Melbourne-based Defence Materials Technology Centre(DMTC) is leading targetted research programmes to improve both vehicular armour systems as well as lightweight ceramic armours for personnel protection.Two of the country’s leading industrial suppliers of military equipment, Thalesand Australian Defence Apparel (ADA), are core participants of DMTC and provide technical leadership.

Capability through collaboration

The DMTC is a joint venture that brings together the defenceindustry, universities and Government research agencies. Established in May 2008, DMTC is Australia’s first Defence Future Capability Technology Centre – aFederal Government initiative based on the successful Cooperative Research Centre (CRC) model that has been running in Australia since the early 1990s.

The centre provides extensive opportunities for applied research across a diverse range of materials and manufacturing technologies. Its industry-led technology development portfolio spans air and maritime platforms, propulsion systems and armour applications, with more than 70 people directly contributing to 18 research projects. Projects incorporate a broad range of materials technologies from high strength steels for armour and maritime applications,through to advanced materials technology enabling the design and fabrication of scramjet combustors for sustained hypersonic flight at Mach 8.

Ballistic protection of military platforms, whether theyare main battle tanks, armoured personnel carriers or helicopters, has always been given a high priority when it comes to defence spending. However, recently, the protection of armed personnel on the battlefield has taken a newdirection – conventional body armour systems are too heavy (in some theatres of operation) as threat levels now include blast, heat and flash, from bombs and improvised explosive devices, as well as high energy fragments and conventional high-velocity rifle bullets. The challenge to develop improved armour materials and manufacturing technologies has never been so great.

High impact

One of DMTC’s projects focuses on ways of enhancing the ballistic performance and/or impact behaviour of small arms protective inserts (otherwise known as SAPI plates). Such micro-engineered, hard armour products consist of a number of highly-specialised materials all carefully chosen to perform a particular function.

The image above shows a cross-section of a SAPI plate in which the strike face is normally a hard, ceramic material chosen to erode or fragment the bullet, and the backing material is normally a high-performance, laminated polymer composite chosen to catch and arrest the fragmented bullet.

The current research project includes work on improved multi-hit performance/behaviour of ceramic armour systems. The image, shows a series of digital X-ray images of a ceramic-faced body armour plate that has been impacted at three specific locations. The damage resulting fromeach sequential impact was recorded in order to study the cumulative damage andits effect upon penetration behaviour and localised failure modes. It is hoped that the project will determine ballistic knock-down factors for each subsequent impact and a new analytical model to predict the behaviour of different designs of body armour systems.

 

 

 

 

It also includes the development of more robust strike-face materials. It is well known that conventional ceramics are brittle solids – this is also the case, unfortunately, for armour-grade ceramics like reaction sintered silicon carbide and hot pressed boron carbide. Ballistic impacts result in extensive cracking (see image above), not only at the site of impact where conoidal fracture occurs, but also via thegeneration of numerous, through-thickness, radial cracks emanating outwardsfrom the point of strike.

The aim of the DMTC project is to assess and/or develop alternative materials, including coated ceramics, fibre-reinforced ceramics, aswell as thin, ultra-high-strength steels. The image below shows an example of asteel fibre reinforced silicon carbide material in which the presence of highstrength steel fibres has significantly limited the growth of thethrough-thickness, radial cracks. This novel material, known as AusShield, isone of a number of new materials the project hopes to develop, understand andapply. AusShield is a patented material supplied by Military CeramicsCorporation, Sydney, Australia.

Personnel survivability

In the near future, DMTC hopes to widen its involvementin the field of personnel protection by commencing a new multimillion dollar programme specifically focused on personnel survivability. The proposal has already been put to interested stakeholders and, with appropriate support,should commence in July 2010. The new programme will span four areas ofR&D, with activities including ballistic – blast and flash protection, signature reducing characteristics, utility – fit and comfort and environmental– protection from airborne threats to personnel including chemical/ biological/radiationand thermal conditions.

Further information

Further information: Australian Defence Apparel