Hybrid Additive Manufactured-Aramid fibre body armour

Body armour is essential to protect personnel in situations where they may be exposed to puncture or penetrative threats. The protective performance of armour can be split into four categories:

1. Blunt trauma protection - often achieved using an Ethylene-Vinyl Acetate (EVA) foam and moulded Acrylonitrile Butadiene Styrene (ABS) outer shell.
2. Stab resistance - typically achieved using a rigid Polycarbonate (PC) chest plate.
3. Ballistic resistance - Lower level protection via a laminated network of aramid or Ultra-High Molecular Weight Polyethylene (UHMWPE) fibre layers, with higher protection achieved using ceramic plates.
4. Multi-threat (stab and ballistic resistance) - Achieved using a combination of aramid/UHMWPE fibres and a PC chest plate.

Whilst protection against ballistic threats can be achieved through the use of aramid-fibre armour, such armour is unsuitable at providing protection against lower velocity sharp force threats such as blades or spikes. This is due to the sharp force threat penetrating between the individual fibrous elements of the armour. Therefore, to achieve stab and ballistic resistance the use of aramid/UHMWPE fibres coupled with a PC chestplate is often required. By doing so, the improved manouverability typically offered by fibre-based armour is substantially reduced. Whilst the protective performance of these articles have progressed since their introduction, users of such armour frequently report of ill-fitting and uncomfortable garments. This, combined with the high weight and low breathability of protective articles such as PC and aramid-based armour, at best results in impaired performance such as reduced running speeds or operational manouevrability, and at worst can lead to physiological effects including nerve damage and severe musculoskeletal injuries.

Additive Manufacturing (AM) is the name for group of manufacturing techniques which can produce extremely complex geometries with little or no additional costs. The use of these processes for the production of clothing has already been demonstrated in the fashion arena with the development of highly articulated linkable textile-like structures. Recent work conducted by the PI has also demonstrated that AM technologies can also be utilised to achieve stab resistance to the internationally recognised UK Home Office body armour protective standards.

This project seeks to utilise the design and manufacturing opportunities offered by AM technologies, coupled with the enhanced protective performance and manouverability of existing aramid-based armour. To achieve this a range of AM material optimisation and Computer Aided Design (CAD) activities, as well as stab and ballistic validation exercises will be performed within the grant period. The development of this hybrid protective system could present a significant leap in the development of the next generation of body armour in which the physical comfort of the wearer and their subsequent operational performance is as important a factor as protective performance. In summary, this research will aim to produce the first generation hybrid AM-aramid fibre body armour panel capable of providing protection against stab and ballistic threats.

The primary and immediate purpose of this research project is to realise the next step in enhancing the protective and operational performance of body armour. In addition, the knowledge gathered and data generated has the potential to make a substantial impact on future policies or standards relating to the design, development, and testing of AM based or hybrid AM-aramid fibre protective body armour.

Dialogue throughout the course of the project will be maintained with the Dr. Tom Payne of the UK Home Office Centre for Applied Science and Technology (CAST) - a world leading authority for the development of test standards for blunt, stab and ballistic resistant body armour. Engaging with CAST not only enables the research team to receive feedback on the progression of the project and input relating to the operational requirements of front-line personnel, but also establishes a platform for both parties to discuss the development of new, or the adaptation of existing body armour standards in relation to the testing of AM-based armour during and beyond the funded period. The development of any new standard for hybrid AM-aramid fibre armour may include topics such as quality control of raw and processed materials, certification of manufacture, ergonomic testing methodologies, in-field maintenance requirements, etc.

In the medium to long term, a range of opportunities exist to further progress the development of the next generation of body armour realised by digital design and manufacturing technologies. For example, through the use of Computer Aided Design (CAD) and AM, opportunities exist to design and manufacture bespoke fitted armour; establish a multi-tiered and multi-threat protection system; operationalise AM printed surfaces to provide additional functionality such as thermal cooling; establish a fully integrated body armour solution that features communication capabilities; simulate field tests to assess wearability and thermal comfort - topics of which may provide the basis for future follow-on grant applications.

This project will not only progress the development of the next generation of body armour in the medium to long term through the use of digital design and manufacturing technologies, but could also disrupt current armour developed in the short-term, leading manufactures to look at innovating their existing products to provide improved wearer comfort. Development of the proposed hybrid AM-aramid fibre armour and subsequent research activities following this initial project, have the potential to benefit front-line emergency service personnel, particularly Police officers. Minimising body armour mass or improving wearer comfort in comparison to existing protective solutions has the potential to enhance the experience of the wearer. Consequently, there is a significant opportunity to enhance the resilience of the domestic safety and security services that use such body armour on a daily basis.