Browsing by Author "Read, James"

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    Evaluation of soft tissue simulant performance against economic and environmental impact
    (Royal Society of Chemistry, 2024-02-22) Read, James; McNaught, Ken R.; Hazael, Rachael; Critchley, Richard
    Soft tissue simulants are traditionally used to provide a post impact medium suitable for replicating human anatomy. Performance of materials is therefore paramount, and the analysis of such experimentation relies on responses that mimic the various tissue, bone and muscle groups contained within the human body. However, with an increasing global push to reduce carbon emissions and increase sustainability, current materials require examination to ensure research establishments remain at the forefront of environmentally friendly practices. To date, the literature contains little in relation to how environmentally friendly the use and supply of soft tissue simulants is. The aim of the research is to provide researchers with primary data to support decisions on material selection for ballistic simulation research. The need arises due to the high cost and environmental impact of existing materials. To explore this research gap, a series of 5.5 mm ball bearings were fired from a gas gun at velocity ranges between 122 and 526 m s−1 to examine the performance characteristics of six commercially available soft tissue simulants and a foodstuffs grade gelatine that represented a more cost effective environmentally friendly alternative. A structured multi-criteria decision analysis approach was employed to compare the overall effectiveness of the alternative materials. It was found that whilst PermaGel, 20 and 10% ballistic gelatine performed the most advantageously respectively during experimental testing, qualitative environmental assessment showed ballistic soap, PermaGel and foodstuffs gelatine to be most advantageous. The information provided within this study will enable researchers to make more informed decisions on both economic and environmental implications when sourcing materials for use within survivability assessment, whilst further work would increase awareness and viability of alternative materials.
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    Penetration performance of protective materials from crossbow attack: a preliminary study
    (Springer, 2023-03-13) Read, James; Hazael, Rachael; Critchley, Richard
    Crossbow-related injuries resulting in serious and mortal consequences have increased in recent years, and although significant research exists for both injury and fatality on the human body, limited data exists on the lethality of the bolt and the failure modes of protective materials. This paper concerns itself with the experimental validation of four differing crossbow bolt geometries, their effects on material failure and potentially lethality. During this study, four different types of crossbow bolt geometries were tested against two protection mechanisms that differed in mechanical properties, geometry, mass and size. The results show that at 67 ms−1, ogive, field and combo tips do not provide lethal effect at 10-m range, whilst a broadhead tip will perforate both the para-aramid and a reinforced area of polycarbonate material consisting of two 3-mm plates at 63–66 ms−1. Although perforation was apparent with a more honed tip geometry, the chain mail layering within the para-aramid protection and friction caused by polycarbonate petalling on the arrow body reduced the velocity enough to demonstrate the materials under test are effective at withstanding crossbow attack. Subsequent calculation of the maximum velocity that arrows could achieve if fired from the crossbow within this study shows results close to the overmatch value of each material and therefore a requirement to advance the knowledge in this field to influence the development of more effective armour protection mechanisms.
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    Quantification of fragmentation capture materials and an assessment of the viability of economical alternatives: a preliminary study
    (The Royal Society, 2023-09-11) Read, James; Ritchie, Thomas; Brown, Laura; Thawani, Bonny; Bloodworth-Race, Susie; Hazael, Rachael; Critchley, Richard
    High pressure, high temperature events need to be quantified experimentally. Where fragmentation occurs i.e. against Personal Protective Equipment (PPE), there is a requirement for both a reliable and repeatable measurement of numerous experimental metrics. Typically, the most critical is calculating the energy absorbed by the target material, to characterise target performance. This is achieved by detonating a device and capturing a proportion of the fragmentation in a suitable material that can achieve successful recovery of all fragmentation produced. Therefore, allowing the estimation of the target’s response using the depth of penetration within the capture material which allows the calculation of energy absorption. The current standardised fragmentation capture material used within the United Kingdom is known as strawboard. Although effective, this material is both expensive and limited in its availability. This study explores the classification of strawboard to provide a suitable baseline to compare against Medium Density Fibreboard (MDF) and flooring underlay which represent two more economically friendly alternatives on the open market. It was found that the uniformity of response for the MDF material was better than that of strawboard, due to its reproducibility between batches and velocity ranges. To further explore this phenomena, high explosive trials were conducted, further demonstrating MDF to be a viable, reliable, and cheaper alternative.
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    Soft tissue simulants for survivability assessment—a sustainability focussed review
    (MDPI, 2022-05-13) Read, James; Hazael, Rachael; Critchley, Richard
    Traditionally, human cadavers and porcine tissue have been used as means to replicate elements of the human body; however, because of the differences in biomechanical properties from the porcine limbs/organs and the potential for degradation of mechanical properties caused by ageing, they do not provide accurate material for either lethality or survivability assessment. In the 21st century and with more ethical ways of working being employed, the use of soft tissue analogues to undertake ballistic testing has become routinely accepted. However, gaps in the literature exist that have identified a difference in material characterisation. Procedurally, every researcher manufactures the gelatine differently, which, when combined with a lack of calibration procedures, can cause inconsistencies in output data, and additional concerns exist surrounding the repeatability of re-mouldable simulants, such as Perma-Gel®. Further, limited information is available on the environmental impact of ‘1 shot’ items, such as ballistic gelatine, which has become a well-known and widely accepted material for survivability assessment. This review identifies key inconsistencies within the literature, the risk associated with survivability assessment, and potential solutions to the issues identified within, with outcomes showing that the current methodologies for survivability assessment do not align with the wider UK government ambition of being Net Zero by 2050 unless changes are made.
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    Sustainable and economical alternatives to fragment capture materials in explosive and ballistic trials
    (Springer, 2024-03-12) Read, James; Quinlan, Philip; Bloodworth-Race, Susie; Hazael, Rachael; Critchley, Richard
    Strawboard has been utilised as a fragmentation capture material since the 1960s, mainly employed to capture fragments from explosives and explosive devices from arena trials of munitions. As this material has historically been calibrated to a known standard, it has a proven record of allowing research establishments to ascertain the velocity of a fragment based on the depth of penetration of the strawboard. During the time of calibration, strawboard was used as a common building material which was both widely available and relatively affordable; however, due to the recent economic crisis and geopolitical supply issues, this is no longer the case. Building on initial testing, this paper investigates alternatives to strawboard to determine if a cheaper, more readily available material can be used instead. The alternatives are compared and judged based on the NATO ARSP-03 guideline for capture material which includes metrics such as price and attainability, as well as assessing environmental impact and its ability to be used as a viable alternative to strawboard in an explosive environment. Based on these NATO guidelines, explosive fragmentation and ballistic experiments were conducted, and ten materials were tested based on the following criteria: Handling, Density, Flammability, Calibration, Cost and Availability. Medium Density Fibreboard (MDF) was found to be a suitable alternative to strawboard. The data demonstrates that it provides the same capture performance as strawboard at approximately a quarter of the cost and is far more readily available. Other materials also showed potential and further testing should be undertaken to validate these materials as alternatives to MDF.