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  • Journal article
    Proud WG, Nguyen T-TN, Bo C, Butler BJ, Boddy RL, Williams A, Masouros S, Brown KAet al., 2015,

    The High-Strain Rate Loading of Structural Biological Materials

    , METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, Vol: 46A, Pages: 4559-4566, ISSN: 1073-5623
  • Journal article
    Spurrier E, Singleton JAG, Gibb I, Masouros S, Clasper Jet al., 2015,

    Blast Injury in the Spine: Dynamic Response Index Is Not an Appropriate Model for Predicting Injury

    , CLINICAL ORTHOPAEDICS AND RELATED RESEARCH, Vol: 473, Pages: 2929-2935, ISSN: 0009-921X
  • Journal article
    Arora H, Tarleton E, Li-Mayer J, Charalambides M, Lewis Det al., 2015,

    Modelling the damage and deformation process in a plastic bonded explosive microstructure under tension using the finite element method

    , Computational Materials Science, Vol: 110, Pages: 91-101, ISSN: 0927-0256

    Modelling the deformation and failure processes occurring in polymer bonded explosives (PBX)and other energetic materials is of great importance for processing methods and lifetime storagepurposes. Crystal debonding is undesirable since this can lead to contamination and a reductionin mechanical properties. An insensitive high explosive (PBX-1) was the focus of the study.This binary particulate composite consists of (TATB) filler particles encapsulated in a polymericbinder (KELF800). The particle/matrix interface was characterised with a bi-linear cohesive law,the filler was treated as elastic and the matrix as visco-hyperelastic. Material parameters weredetermined experimentally for the binder and the cohesive parameters were obtained previouslyfrom Williamson et al. (2014) and Gee et al. (2007) for the interface. Once calibrated, the materiallaws were implemented in a finite element model to allow the macroscopic response of thecomposite to be simulated. A finite element mesh was generated using a SEM image to identifythe filler particles which are represented as a set of 2D polygons. Simulated microstructureswere also generated with the same size distribution and volume fraction only with the idealisedassumption that the particles are a set of circles in 2D and spheres in 3D. The various modelresults were compared and a number of other variables were examined for their influence on theglobal deformation behaviour such as strain rate, cohesive parameters and contrast between fillerand matrix modulus. The overwhelming outcome is that the geometry of the particles plays acrucial role in determining the onset of failure and the severity of fracture in relation to whetherit is a purely local or global failure. The model was validated against a set of uniaxial tensiletests on PBX-1 and it was found that it predicted the initial modulus and failure stress and strainwell.Keywords: Particulate composites, High volume fraction, Finite Element Analysis,Micromechanics, Fract

  • Journal article
    Kelly M, Arora H, Worley A, Kaye M, Del Linz P, Hooper PA, Dear JPet al., 2015,

    Sandwich panel cores for blast applications: materials and graded density

    , Experimental Mechanics, Vol: 56, ISSN: 1741-2765

    Sandwich composites are of interest in marine applications dueto their high strength-to-weight ratio and tailorable mechanical properties, but their resistance to air blast loading is not well understood. Full-scale 100 kg TNT equivalent air blast testing at a 15 m stand-off distance wasperformed on glass-fibre reinforced polymer (GFRP) sandwich panels withpolyvinyl chloride (PVC); polymethacrylimid (PMI); and styrene acrylonitrile(SAN) foam cores, all possessing the same thickness and density. Further testingwas performed to assess the blast resistance of a sandwich panel containinga stepwise graded density SAN foam core, increasing in density away from theblast facing side. Finally a sandwich panel containing compliant polypropylene(PP) fibres within the GFRP front face-sheet, was subjected to blast loadingwith the intention of preventing front face-sheet cracking during blast. Measurementsof the sandwich panel responses were made using high-speed digital image correlation (DIC), and post-blast damage was assessed by sectioning thesandwich panels and mapping the damage observed. It was concluded that allcores are effective in improving blast tolerance and that the SAN core wasthe most blast tolerant out of the three foam polymer types, with the DIC resultsshowing a lower deflection measured during blast, and post-blast visualinspections showing less damage suffered. By grading the density of the core itwas found that through thickness crack propagation was mitigated, as well asdamage in the higher density foam layers, thus resulting in a smoother backface-sheet deflection profile. By incorporating compliant PP fibres into thefront face-sheet, cracking was prevented in the GFRP, despite damage beingpresent in the core and the interfaces between the core and face-sheets.

  • Journal article
    Reichenbach JDT, Meltzer B, Reichenbach CS, Braiman C, Schiff ND, Hudspeth AJet al., 2015,

    The steady-state response of the cerebral cortex to the beat of music reflects both the comprehension of music and attention

    , Frontiers in Human Neuroscience, Vol: 9, ISSN: 1662-5161

    The brain's analyses of speech and music share a range of neural resources and mechanisms. Music displays a temporal structure of complexity similar to that of speech, unfolds over comparable timescales, and elicits cognitive demands in tasks involving comprehension and attention. During speech processing, synchronized neural activity of the cerebral cortex in the delta and theta frequency bands tracks the envelope of a speech signal, and this neural activity is modulated by high-level cortical functions such as speech comprehension and attention. It remains unclear, however, whether the cortex also responds to the natural rhythmic structure of music and how the response, if present, is influenced by higher cognitive processes. Here we employ electroencephalography (EEG) to show that the cortex responds to the beat of music and that this steady-state response reflects musical comprehension and attention. We show that the cortical response to the beat is weaker when subjects listen to a familiar tune than when they listen to an unfamiliar, nonsensical musical piece. Furthermore, we show that in a task of intermodal attention there is a larger neural response at the beat frequency when subjects attend to a musical stimulus than when they ignore the auditory signal and instead focus on a visual one. Our findings may be applied in clinical assessments of auditory processing and music cognition as well as in the construction of auditory brain-machine interfaces.

  • Journal article
    Butler BJ, Bo C, Boddy RL, Arora H, Williams A, Proud WG, Brown KAet al., 2015,

    Composite nature of fresh skin revealed during compression

    , Bioinspired, Biomimetic and Nanobiomaterials, Vol: 4, Pages: 133-139, ISSN: 2045-9858
  • Journal article
    Cleather DJ, Bull AM, 2015,

    The development of a segment-based musculoskeletal model of the lower limb: introducing FreeBody.

    , Royal Society Open Science, Vol: 2, ISSN: 2054-5703

    Traditional approaches to the biomechanical analysis of movement are joint-based; that is the mechanics of the body are described in terms of the forces and moments acting at the joints, and that muscular forces are considered to create moments about the joints. We have recently shown that segment-based approaches, where the mechanics of the body are described by considering the effect of the muscle, ligament and joint contact forces on the segments themselves, can also prove insightful. We have also previously described a simultaneous, optimization-based, musculoskeletal model of the lower limb. However, this prior model incorporates both joint- and segment-based assumptions. The purpose of this study was therefore to develop an entirely segment-based model of the lower limb and to compare its performance to our previous work. The segment-based model was used to estimate the muscle forces found during vertical jumping, which were in turn compared with the muscular activations that have been found in vertical jumping, by using a Geers' metric to quantify the magnitude and phase errors. The segment-based model was shown to have a similar ability to estimate muscle forces as a model based upon our previous work. In the future, we will evaluate the ability of the segment-based model to be used to provide results with clinical relevance, and compare its performance to joint-based approaches. The segment-based model described in this article is publicly available as a GUI-based Matlab® application and in the original source code (at www.msksoftware.org.uk).

  • Book chapter
    Halewood C, Masouros S, Amis AA, 2015,

    Structure and function of the menisci

    , Meniscal Allograft Transplantation. A comprehensive review., Editors: Getgood, Spalding, Cole, Gersoff, Verdonk, ISBN: 978-0-9558873-5-2
  • Conference paper
    Villette CC, Phillips ATM, Zaharie DT, 2015,

    Frangible optimised lower limb surrogate for assessing underbelly blast injury

    , International Research Council on Biomechanics of Injury
  • Conference paper
    Koziakova M, Harris K, Campos-Pires R, Malhotra D, Franks N, Dickinson Ret al., 2015,

    The neuroprotective efficacy of noble gases in an in vitro model of ischemic brain injury.

    , British Neuroscience Association, Publisher: BNA
  • Conference paper
    Campos-Pires R, Sebastiani A, Hirnet T, Luh C, Radyushkin K, Thal S, Franks N, Dickinson Ret al., 2015,

    Xenon provides short term & long term neuroprotection in an in vivo model of traumatic brain injury

    , British Neuroscience Associaton
  • Conference paper
    Campos-Pires R, Armstrong S, Sebastiani A, Hirnet T, Luh C, Radyushkin K, Thal S, Franks N, Dickinson Ret al., 2015,

    Xenon provides short term & long term neuroprotection in an in vivo model of traumatic brain injury.

    , BNA Festival of Neuroscience, Pages: 1-1
  • Journal article
    Arora H, Kelly M, Worley A, Del Linz P, Fergusson A, Hooper PA, Dear JPet al., 2015,

    Compressive strength after blast of sandwich composite materials.

    , Philosophical Transactions A: Mathematical, Physical and Engineering Sciences, Vol: 372, ISSN: 1471-2962

    Composite sandwich materials have yet to be widely adopted in the construction of naval vessels despite their excellent strength-to-weight ratio and low radar return. One barrier to their wider use is our limited understanding of their performance when subjected to air blast. This paper focuses on this problem and specifically the strength remaining after damage caused during an explosion. Carbon-fibre-reinforced polymer (CFRP) composite skins on a styrene-acrylonitrile (SAN) polymer closed-cell foam core are the primary composite system evaluated. Glass-fibre-reinforced polymer (GFRP) composite skins were also included for comparison in a comparable sandwich configuration. Full-scale blast experiments were conducted, where 1.6×1.3 m sized panels were subjected to blast of a Hopkinson-Cranz scaled distance of 3.02 m kg(-1/3), 100 kg TNT equivalent at a stand-off distance of 14 m. This explosive blast represents a surface blast threat, where the shockwave propagates in air towards the naval vessel. Hopkinson was the first to investigate the characteristics of this explosive air-blast pulse (Hopkinson 1948 Proc. R. Soc. Lond. A 89, 411-413 (doi:10.1098/rspa.1914.0008)). Further analysis is provided on the performance of the CFRP sandwich panel relative to the GFRP sandwich panel when subjected to blast loading through use of high-speed speckle strain mapping. After the blast events, the residual compressive load-bearing capacity is investigated experimentally, using appropriate loading conditions that an in-service vessel may have to sustain. Residual strength testing is well established for post-impact ballistic assessment, but there has been less research performed on the residual strength of sandwich composites after blast.

  • Journal article
    Phillips ATM, Villette CC, Modenese L, 2015,

    Femoral bone mesoscale structural architecture prediction using musculoskeletal and finite element modelling

    , International Biomechanics, Vol: 2, Pages: 43-61, ISSN: 2333-5432

    Through much of the anatomical and clinical literature bone is studied with a focus on its structural architecture, while it is rare for bone to be modelled using a structural mechanics as opposed to a continuum mechanics approach in the engineering literature. A novel mesoscale structural model of the femur is presented in which truss and shell elements are used to represent trabecular and cortical bone, respectively. Structural optimisation using a strain-based bone adaptation algorithm is incorporated within a musculoskeletal and finite element modelling framework to predict the structure of the femur subjected to two loading scenarios; a single load case corresponding to the frame of maximum hip joint contact force during walking and a full loading regime consisting of multiple load cases from five activities of daily living. The use of the full loading regime compared to the single load case has a profound influence on the predicted trabecular and cortical structure throughout the femur, with dramatic volume increases in the femoral shaft and the distal femur, and regional increases at the femoral neck and greater trochanter in the proximal femur. The mesoscale structural model subjected to the full loading regime shows agreement with the observed structural architecture of the femur while the structural approach has potential application in bone fracture prediction, prevention and treatment. The mesoscale structural approach achieves the synergistic goals of computational efficiency similar to a macroscale continuum approach and a resolution nearing that of a microscale continuum approach.

  • Conference paper
    Villette CC, Phillips ATM, 2015,

    Predictive mesoscale structural modelling of bone informed by microscale poroelastic analyses

    , XXV congress of the International Society of Biomechanics
  • Conference paper
    Zaharie D, Villette C, Phillips A, 2015,

    FRANGIBLE OPTIMISED LOWER LIMB SURROGATE FOR ASSESSING INJURY CAUSED BY UNDERBELLY BLAST

    , XV International Symposium on Computer Simulation in Biomechanics
  • Journal article
    Campos-Pires R, Armstrong SP, Sebastiani A, Luh C, Gruss M, Radyushkin K, Hirnet T, Werner C, Engelhard K, Franks NP, Thal SC, Dickinson Ret al., 2015,

    Xenon Improves Neurologic Outcome and Reduces Secondary Injury Following Trauma in an In Vivo Model of Traumatic Brain Injury

    , Critical Care Medicine, Vol: 43, Pages: 149-158, ISSN: 1530-0293

    Objectives: To determine the neuroprotective efficacy of the inert gas xenon following traumatic brain injury and to determine whether application of xenon has a clinically relevant therapeutic time window.Design: Controlled animal study.Setting: University research laboratory.Subjects: Male C57BL/6N mice (n = 196).Interventions: Seventy-five percent xenon, 50% xenon, or 30% xenon, with 25% oxygen (balance nitrogen) treatment following mechanical brain lesion by controlled cortical impact.Measurements and Main Results: Outcome following trauma was measured using 1) functional neurologic outcome score, 2) histological measurement of contusion volume, and 3) analysis of locomotor function and gait. Our study shows that xenon treatment improves outcome following traumatic brain injury. Neurologic outcome scores were significantly (p < 0.05) better in xenon-treated groups in the early phase (24 hr) and up to 4 days after injury. Contusion volume was significantly (p < 0.05) reduced in the xenon-treated groups. Xenon treatment significantly (p < 0.05) reduced contusion volume when xenon was given 15 minutes after injury or when treatment was delayed 1 or 3 hours after injury. Neurologic outcome was significantly (p < 0.05) improved when xenon treatment was given 15 minutes or 1 hour after injury. Improvements in locomotor function (p < 0.05) were observed in the xenon-treated group, 1 month after trauma.Conclusions: These results show for the first time that xenon improves neurologic outcome and reduces contusion volume following traumatic brain injury in mice. In this model, xenon application has a therapeutic time window of up to at least 3 hours. These findings support the idea that xenon may be of benefit as a neuroprotective treatment in patients with brain trauma.

  • Journal article
    Bonner TJ, Newell N, Karunaratne A, Pullen AD, Amis AA, Bull AMJ, Masouros SDet al., 2015,

    Strain-rate sensitivity of the lateral collateral ligament of the knee

    , JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS, Vol: 41, Pages: 261-270, ISSN: 1751-6161
  • Conference paper
    Reichenbach T, Stefanovic A, Nin F, Hudspeth AJet al., 2015,

    Otoacoustic Emission Through Waves on Reissner's Membrane

    , 12th International Workshop on the Mechanics of Hearing, Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Journal article
    Kelly M, Arora H, Dear JP, 2014,

    The comparison of various foam polymer types in composite sandwich panels subjected to full scale air blast loading

    , Procedia Engineering, Vol: 88, Pages: 48-53, ISSN: 1877-7058

    Full scale air blast testing has been performed on a range of polymeric foam composite panels. These panels employed glass fibre reinforced polymer (GFRP) face-sheets with different polymer foam cores, namely: Styrene acrylonitrile (SAN); Polyvinylchloride (PVC) and Polymethacrylimide (PMI). The three sandwich panels were all subjected to 100 kg TNT equivalent blast loading at a stand-off distance of 15 m, and the responses of the panels were measured using Digital Image Correlation (DIC). The extent of damage in the sandwich panels was then inspected via post-blast sectioning, and it was found that the SAN core suffered the least damage, and the PMI suffered the most. The DIC showed that the deflection of the SAN core sandwich panel was much less than the other two foam polymer cores, due to less damage meaning a greater stiffness was retained. All blast research to date is part of a programme sponsored by the Office of Naval Research (ONR).

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