Imperial College London

Dr William G Proud

Faculty of Natural SciencesDepartment of Physics

Reader in Shock Physics
 
 
 
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Contact

 

+44 (0)20 7594 5898w.proud

 
 
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Location

 

727Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

231 results found

Sory DR, Amin HD, Chapman D, Proud WG, Rankin SMet al., 2020, Replicating landmine blast loading in cellular <i>in Vitro</i> models, Physical Biology, Vol: 17, ISSN: 1478-3967

Trauma arising from landmines and improvised explosive devices promotes heterotopic ossification, the formation of extra-skeletal bone in non-osseous tissue. To date, experimental platforms that can replicate the loading parameter space relevant to improvised explosive device and landmine blast wave exposure have not been available to study the effects of such non-physiological mechanical loading on cells. Here, we present the design and calibration of three distinct in vitro experimental loading platforms that allow us to replicate the spectrum of loading conditions recorded in near-field blast wave exposure. We subjected cells in suspension or in a three-dimensional hydrogel to strain rates up to 6000 s-1and pressure levels up to 45 MPa. Our results highlight that cellular activation is regulated in a non-linear fashion - not by a single mechanical parameter, it is the combined action of the applied mechanical pressure, rate of loading and loading impulse, along with the extracellular environment used to convey the pressure waves. Finally, our research indicates that PO MSCs are finely tuned to respond to mechanical stimuli that fall within defined ranges of loading.

Journal article

Nguyen TT, Carpanen D, Rankin I, Ramasamy A, Breeze J, Proud W, Clasper J, Masouros Set al., 2020, Mapping the risk of fracture of the tibia from penetrating fragments, Frontiers in Bioengineering and Biotechnology, Vol: 8, Pages: 1-11, ISSN: 2296-4185

Penetrating injuries are commonly inflicted in attacks with explosive devices. The extremities, and especially the leg, are the most commonly affected body areas, presenting high risk of infection, slow recovery, and threat of amputation. The aim of this study was to quantify the risk of fracture to the anteromedial, posterior, and lateral aspects of the tibia from a metal fragment-simulating projectile (FSP). A gas gun system and a 0.78-g cylindrical FSP were employed to perform tests on an ovine tibia model. The results from the animal study were subsequently scaled to obtain fracture-risk curves for the human tibia using the cortical thickness ratio. The thickness of the surrounding soft tissue was also taken into account when assessing fracture risk. The lateral cortex of the tibia was found to be most susceptible tofracture,whose impact velocity at 50% risk of EF1+, EF2+, EF3+, and EF4+ fracture types –according to the modified Winquist-Hansen classification –were 174, 190, 212,and 282 m/s respectively. The findings of this study will be used to increase the fidelity of predictive models of projectile penetration.

Journal article

Proud WG, O'Brien S, Wilson MA, 2020, Elicitation of knowledge from a defence expert, ISSN: 1742-6588

The aim of this work is to understand the way that a defence expert defines the concept of importance in relation to the ideas contained in a scientific document. The expert's views on the importance of the concepts in this document were elicited in two phases. In the first phase, the expert was asked to summarise an eight-page document on the effects of electromagnetic fields on propellant combustion. Completion of this task generated a series of 'key points'. Phase two of the methodology was a sit-down interview with the expert. This interview comprised three parts: asking the expert to talk through why each of the key points were important, asking the expert to sort the key points into categories according to how important they are and then asking the expert to generate categories of why the points are important. The techniques used for expert elicitation proved highly successful in relation to this domain of knowledge. Not only were the procedures able to extract the underlying categories through which the expert structured their understanding of the field, but the results indicated reliability in the content of knowledge extracted through different methods. Subsequent papers in this project compare this work to parallel analysis conducted using Natural Language Processing tools.

Conference paper

Felten M, Fries M, Pullen A, Proud WG, Jung Aet al., 2020, Investigation of Strain-Rate Effects in Ni/PU Hybrid Foams under Low-Impact Velocities, ADVANCED ENGINEERING MATERIALS, Vol: 22, ISSN: 1438-1656

Journal article

Nguyen TT, Carpanen D, Stinner D, Rankin I, Ramasamy A, Breeze J, Proud W, Clasper J, Masouros Set al., 2020, The risk of fracture to the tibia from a fragment simulating projectile, Journal of The Mechanical Behavior of Biomedical Materials, Vol: 102, ISSN: 1751-6161

Penetrating injuries due to fragments energised by an explosive event are life threatening and are associated with poor clinical and functional outcomes. The tibia is the long bone most affected in survivors of explosive events, yet the risk of penetrating injury to it has not been quantified. In this study, an injury-risk assessment of penetrating injury to the tibia was conducted using a gas-gun system with a 0.78-g cylindrical fragment simulating projectile. An ovine tibia model was used to generate the injury-risk curves and human cadaveric tests were conducted to validate and scale the results of the ovine model. The impact velocity at 50% risk (±95% confidence intervals) for EF1+, EF2+, EF3+, and EF4+ fractures to the human tibia – using the modified Winquist-Hansen classification – was 271 ± 30, 363 ± 46, 459 ± 102, and 936 ± 182 m/s, respectively. The scaling factor for the impact velocity from cadaveric ovine to human was 2.5. These findings define the protection thresholds to improve the injury outcomes for fragment penetrating injury to the tibia.

Journal article

Magnus D, Sory DR, Lee J, Khan MA, Proud WGet al., 2020, Study of Soft Material Blast Mitigation Effects Using a Shock Tube, 21st Biennial American-Physical-Society -Topical-Group Conference on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Proud WG, Martin E, Tear GR, Sory DRet al., 2020, The Effect of Temperature on the Failure of a Simple Perspex Structure, 21st Biennial American-Physical-Society -Topical-Group Conference on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Lee JJ, Sory DR, Proud WG, 2020, Simulation of Two-gauge Measurement Method on the SHPB for Testing Soft Materials, 21st Biennial American-Physical-Society -Topical-Group Conference on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Pissarenko A, Yang W, Quan H, Brown KA, Williams A, Proud WG, Meyers MAet al., 2019, Tensile behavior and structural characterization of pig dermis, ACTA BIOMATERIALIA, Vol: 86, Pages: 77-95, ISSN: 1742-7061

Journal article

Nguyen T-T, Pearce AP, Carpanen D, Sory D, Grigoriadis G, Newell N, Clasper J, Bull A, Proud WG, Masouros SDet al., 2019, Experimental platforms to study blast injury, Journal of the Royal Army Medical Corps, Vol: 165, Pages: 33-37, ISSN: 2052-0468

Injuries sustained due to attacks from explosive weapons are multiple in number, complex in nature, and not well characterised. Blast may cause damage to the human body by the direct effect of overpressure, penetration by highly energised fragments, and blunt trauma by violent displacements of the body. The ability to reproduce the injuries of such insults in a well-controlled fashion is essential in order to understand fully the unique mechanism by which they occur, and design better treatment and protection strategies to alleviate the resulting poor long-term outcomes. This paper reports a range of experimental platforms that have been developed for different blast injury models, their working mechanism, and main applications. These platforms include the shock tube, split-Hopkinson bars, the gas gun, drop towers and bespoke underbody blast simulators.

Journal article

Magnus D, Khan MA, Proud WG, 2018, Epidemiology of civilian blast injuries inflicted by terrorist bombings from 1970-2016, DEFENCE TECHNOLOGY, Vol: 14, Pages: 469-476, ISSN: 2214-9147

Journal article

Nguyen TT, Carpanen D, Tear G, Stinner D, Clasper J, Proud W, Masouros Set al., 2018, Fragment Penetrating Injury to the tibia, Personal Armour Systems Symposia 2018

Conference paper

Butler BJ, Williams A, Tucker AW, Proud WG, Brown KAet al., 2018, Comparative quasi-static mechanical characterization of fresh and stored porcine trachea specimens, 12th International Conference of the European-Association-for-the-Promotion-of-Research-into-the-Dynamic-Behaviour-of-Materials-and-its-Applications (DYMAT-Association), Publisher: SPRINGER HEIDELBERG, Pages: 55-60, ISSN: 1951-6355

Conference paper

Sory DR, Amin HD, Rankin SM, Proud WGet al., 2018, Osteogenic Differentiation of Periosteum-Derived Stromal Cells in Blast-Associated Traumatic Loading, 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Nguyen T-TN, Tear GR, Masouros SD, Proud WGet al., 2018, Fragment Penetrating Injury to Long Bones, 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Brown KA, Butler BJ, Sory D, Nguyen T-TN, Williams A, Proud WGet al., 2018, Challenges in the Characterization of Failure and Resilience of Biological Materials, 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Tear GR, Chapman DJ, Proud WG, Ottley PR, Cullis IG, Gould PJ, Jones AWet al., 2018, The use of PDV to understand damage in rocket motor propellants, 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AIP Publishing, ISSN: 1551-7616

Photonic Doppler Velocimetry (PDV) has been fielded on small scale fragment impact experiments on double base propellant. A 130 mm block of propellant was impacted with a 20 mm diameter cylinder at 1003 ± 10 m s-1 and four PDV probes recorded rear surface motion at different radial distances between 10 mm and 60 mm from impact centre. The PDV was fielded alongside high speed video diagnostics using a dichroic mirror which reflected visible light whilst transmitting the 1550 nm wavelength which the PDV operated at. The rear surface velocity was compared to 2D numerical simulations of the experiment and found to be in good agreement. Additional material moving at up to 2 km s-1 was detected at break out.

Conference paper

Tear G, Cohen A, Magnus D, Sory D, Proud Wet al., 2018, Damage characterisation for cement and concrete using microwave induced damage, International Conference on Experimental Mechanics, Publisher: MDPI, ISSN: 2504-3900

Damage leading to failure in concrete and related materials is a complex behavior. Whilst many numerical approaches are available for simulating the degradation of material strength, it is difficult to discriminate between these models experimentally in the high strain rate ballistic impact regime. An experimental method has been developed to determine when local material failure has occurred, and whether the failure can be classed as fracture or granular flow. This method is tested on Kolsky bar and ballistic impact experiments. Comparison with numerical simulations is presented.

Conference paper

Nguyen TN, Sory DR, Rankin SM, Proud WG, Amin HDet al., 2018, Platform development for primary blast injury studies, Trauma (United Kingdom), ISSN: 1460-4086

© 2018, The Author(s) 2018. Explosion-related injuries are currently the most commonly occurring wounds in modern conflicts. They are observed in both military and civilian theatres, with complex injury pathophysiologies. Primary blast injuries are the most frequently encountered critical injuries experienced by victims close to the explosion. They are caused by large and rapid pressure changes of the blast waves which produce a wide range of loading patterns resulting in varied injuries. Well-characterised experimental loading devices which can reproduce the real mechanical characteristics of blast loadings on biological specimens in in vivo, ex vivo, and in vitro models are essential in determining the injury mechanisms. This paper discusses the performance and application of platforms, including shock tubes, mechanical testing machines, drop-weight rigs, and split-Hopkinson pressure bar, with regards to the replication of primary blast.

Journal article

Magnus D, Smith LC, Proud WG, 2018, Multiple Wave Compression of Granular Materials Using the Split-Hopkinson Pressure Bar, 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Proud WG, Ellison K, Yapp SH, Cole C, Galimberto Set al., 2018, The Response of Simple Polymer Structures to Dynamic Loading, 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Magnus D, Haller A, Jouffroy A, Proud WGet al., 2018, Tensile Characterisation of the Aorta across Quasi-static to Blast Loading Strain Rates, 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Tear GR, Chapman DJ, Eakins D, Proud Wet al., 2017, Birefringence measurements in single crystal sapphire and calcite shocked along the a axis, Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter, Publisher: AIP Publishing, ISSN: 1551-7616

Calcite and sapphire were shock compressed along the ⟨101⎯⎯0⟩ direction (a axis) in a plate impact configuration. Polarimetery and Photonic Doppler Velocimetery (PDV) were used to measure the change in birefringence with particle velocity in the shock direction. Results for sapphire agree well with linear photoelastic theory and current literature showing a linear relationship between birefringence and particle velocity up to 310 m s−1. A maximum change in birefringence of 5% was observed. Calcite however showed anomolous behaviour with no detectable change in birefringence (less than 0.1%) over the range of particle velocities studied (up to 75 m s−1).

Conference paper

Nguyen T-TN, Proud WG, 2017, An Investigation of A Reticulated Foam - Perforated Steel Sheet Combination As A Blast Mitigation Structure, 19th Biennial American-Physical-Society (APS) Conference on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Khan AS, Wilgeroth J, Balzer J, Proud WGet al., 2017, Comparison of Epoxy-Based Encapsulating Materials over Temperature and Strain Rate, 19th Biennial American-Physical-Society (APS) Conference on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Khan AS, Proud WG, 2017, Temperature and Strain Rate Effects on the Piezoelectric Charge Production of PZT 95/5, 19th Biennial American-Physical-Society (APS) Conference on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Proud WG, Chapman DJ, Eakins DE, 2017, The stress and ballistic properties of granular materials, 19th Biennial American-Physical-Society (APS) Conference on Shock Compression of Condensed Matter (SCCM), Publisher: AIP Publishing, ISSN: 1551-7616

Granular materials are widespread in nature and in manufacturing. Their particulate nature gives a compressive strength of a similar order of magnitude as many continuous solids, a vanishingly small tensile strength and variable shear strength, highly dependent on the loading conditions. Previous studies have shown the effect of composition, morphology and particle size, however, compared to metals and polymers, granular materials are not so well understood. This paper will present some recent results for granular materials, placing these within the wider context. Two areas will be dealt with (i) the effect of the skeletal strength of the material and (ii) the displacements associated with ballistic impact. One clear observation is the similarity of behavior of quartz-sands in compression across a range of particle size. However, the precise pathway of compression is strongly dependent on the initial conditions e.g. density and connectivity within the granular bed, as emphasized by some data for quasi-static compression of sand. To fully embrace the range of behaviours seen requires the development of a suitable parameter to describe the material, the paper concludes with a discussion of one of those approaches.

Conference paper

Butler BJ, Sory DR, Nguyen T-TN, Proud WG, Williams A, Brown KAet al., 2017, Characterization of Focal Muscle Compression Under Impact Loading, 19th Biennial American-Physical-Society (APS) Conference on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Sory DR, Areias AC, Overby DR, Proud WGet al., 2017, Novel method to dynamically load cells in 3D-hydrogels culture for blast injury studies, 19th Biennial American-Physical-Society (APS) Conference on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Badham H, Chalmers M, Thuy-Tien NN, Proud WGet al., 2017, The Propagation of Blast Pulses through Dampened Granular Media, 19th Biennial American-Physical-Society (APS) Conference on Shock Compression of Condensed Matter (SCCM), Publisher: AIP Publishing, ISSN: 1551-7616

The propagation of stress through granular and dampened granular material has been reported previously, the addition of significant amounts of liquid in granular beds causes the mechanism of transmission of blast from one of percolation through the bed pores to one of stress transmission through the granules of the bed. It has been shown, however, that limited amounts liquid can retard propagation within blast-loaded beds by approximately an order of magnitude. This paper presents data on percolation through dampened granular beds using a shock tube as the pressure driver. The effect of particle shape and size was investigated using angular grains of quartz sand as well as smooth glass microspheres. The effect of addition of small amounts of liquids is presented.

Conference paper

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