A series of nanocrystalline copper metallised and non-metallised Laser Sintered (LS) Nylon (PA2200) samples using the EOS P100 Formiga system, were stab tested to current Home Office Scientific Development Branch (HOSDB) Knife Resistance (KR) 2007 standards, to ascertain their stab resistant characteristics. The research demonstrated that while a sample thickness of 8mm virgin PA2200 was required for a successful stab test, this figure was significantly reduced to 5.6mm using a 50:50 mix of virgin and recycled PA2200. A further significant reduction in sample thickness to 4.5mm was also recorded for samples manufactured from virgin PA2200, metallised in a 150μm layer of nanocrystalline copper.The results of the stab testing series were then utilised to develop a non-metallised, scale Additive Manufactured (AM) textile manufactured from a 50:50 recycled and virgin PA2200 mix. Results indicated a successful AM textile-like design, with little or no penetration during stab testing at the HOSDB KR1 standard.

With additive manufacturing increasingly being embraced in the area of sports technology, focus has shifted toward cellular structures for impact protection. Periodic lattice structures can be tailored for a specific response by modifying the geometry of individual cells, with the structure capable of being modified to conform around a given body. However, the effect of modifying specific design characteristics within a lattice and the interrelationships between them are not well understood. This study examines five geometric design variables: cell width, strut cross-sectional area (CSA), strut shape, cell orientation, and joint filleting, and their effect on the compressive behavior of a lattice structure. Truncated octahedron lattices were manufactured using nylon through the process of material extrusion and tested under compression at a constant strain rate of 1.0 s-1. Design of experiments was utilized to analyze the results by implementing a 2 (5-1) factorial design. Results indicated that the strut CSA, cell width, and interaction between the two design characteristics had the largest effects on the plateau stress of the lattice and its energy capacity.

The design and assessment of bio-inspired Additive Manufactured stab resistant armour The performance of modern fibre-based or Polycarbonate armour has significantly progressed since their introduction, providing protection against a range of low and high velocity threats. While this is so, users of such armour frequently report of issues relating to their operational suitability resulting in impaired performance and physiological effects. Recently researchers have focussed on how naturally occurring protective mechanisms could be utilised to enhance the protective and operational performance of wearers of engineered body armour. The research presented within this paper therefore utilises a series of key design characteristics exhibited within naturally occurring elasmoid scale armour, coupled with established Laser Sintering manufacturing parameters, for the realisation and assessment of a scale-based stab resistant armoured structure to internationally recognised test standards.

Acetabular fractures in older patients are challenging to manage. The “fix and replace” construct may present a new paradigm for the management of these injuries. We present the current challenge of acetabular fractures in older patients. We present this in the context of the current literature. This invited editorial presents early results from our centre and the ongoing challenges are discussed.

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