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  • Mechanical Behaviour ofMechanical Behaviour of Highly Packed Particulate Composites

    Henry Tany School of Engineering, University of Aberdeen, UK

  • Highly Packed Particulate Composites (HPPCs)

  • Five topics on the “Mechanical Behaviour of  “Highly Packed Particulate Composites” (HPPCs)

    1. Microstructure of Highly Packed Particulate  CompositesComposites

    2. Interface Cohesive Law 3. Network Formation and Percolation Modelling3. Network Formation and Percolation Modelling 4. Materials Point Method and X‐Ray tomography 5. Catastrophic Behaviours under Loading5. Catastrophic Behaviours under Loading

  • Mechanical Behaviour of Highly Packed particulate Composites (HPPCs)g y ac ed pa t cu ate Co pos tes ( Cs)

    1 Microstructure of HPPCs1. Microstructure of HPPCs

  • Structured Food

    One of the greatest challenges in the food industries is to develop products that can  fracture in a pre‐designed way so that they can provide the required function. 

  • Sedimentary Rock

    Sedimentary rocks are made of sediments cemented or compacted  together by a particular force or process over time.

    P ti l i 50

    Mudstone, 泥岩 Conglomerate , 砾岩 Sandstone, 砂岩

    S di t k l t th ti fl d

    Particle size  2mm Particle size 

  • Multiple Sizes

  • Plants

    bamboo poplar eucalypt pine

  • Cellular Structure of Wood

    bamboo poplar eucalypt pine

    Mayo, Evans, Chen, Lagerstrom, 2009, Journal of Physics

  • FoamMaterialsFoam Materials

  • Nacre


    organic  biopolymerbiopolymer

    Brick‐and‐mortar like network. 

    Li X, Huang Z (2009) Unveiling the Formation 

    aragonite  platelets

    Mechanism of Pseudo‐Single‐Crystal Aragonite  Platelets in Nacre, Phys Rev Lett.

  • Hierarchical Organization in Nacre

    crystal / biological binderBrick‐mortar network biological binderBrick mortar network


    Luz and Mano , 2009

    Brick‐mortar network

  • Plastic Bonded Energetic Materialg

    coarse particlesp (~250 m)

    fine particles  (~8m) 

    High volume fraction ~93%g

    High specific surface of interface

  • Bimodal Size Distribution

  • Safety in Nuclear Decommissioning

    Partnership with Sellafield Ltd Decommissioning, Cumbria, 2007 -p g, ,

    Explosive charges placed under the cooling towers of Calder Hall Plant

    Controlled collapse of each tower. (World Nuclear News)cooling towers of Calder Hall Plant.

    A d t di f th iti it f l i t f d t l

    (World Nuclear News)

    An understanding of the sensitivity of explosives at a fundamental  level is important for safety in nuclear decommissioning.

  • Solid Propellant Rocket

    DDT: normal surface burning ‐>explosion

    Catastrophic interface debonding ‐> formation of hotspot

    Microstructure of solid propellant material. Id l 1999

    Center for Simulation of Advanced Rockets, UIUC

    Ide et al., 1999 • Ignition and combustion of composite energetic materials • Solid mechanics of propellant, case, insulation, and nozzle • Fluid dynamics of interior flow and exhaust plume

  • Pressure – Burn – Microstructure

    Combustion  chamber

    Solid propellant

    BurningBurning  surface

    Relatively small defects, like debonded interfaces and cracks, can lead to catastrophic failure.

  • Summary y

    Several typical Highly Packed Particulate Composites (HPPCs)