Welcome to the page of Stephen Hall's Granular Mechanics research.
This page contains information about research that is being carried out at the Division of Solid Mechanics at Lund University, in collaboration with others, in the general area of Granular Mechanics.
This research is funded primarily by a Marie Curie Career Integration Grant (CIG) under Framework 7 and two projects funded by the Swedish Research Agency (VR):
- MC-CIG: 321924 - Combined 4D experimental grain-scale characterisation of grain-strains, force transfer and kinematics in natural granular material (sand) under load (2013-2016)
- VR: Evolving elasticity, damage and localised failure in porous granular rocks (2013-2015)
- VR: Granular mechanics (2016-2019)
Granular materials, such as sand, are complex systems in which relatively simple building blocks (i.e., contacting particles - sand grains) behave and interact collectively and in complicated ways. These interactions produce structural evolution over a range of different spatial and temporal scales from contacting-particle interactions to intermediate (meso-) scale communication and structure formation (e.g., localised deformation such as shear bands) to longer-range pattern formation. These kinematic effects are associated with the build-up of stress and possible relaxation via structural reorganisation and particle damage. This research tackles the experimental challenge of characterizing the mechanics of granular materials and, in particular, the quest for one of the holy grails of granular mechanics: the combined measurement of the kinematics and force transmission in real 3D materials during loading. The research has implications in terrestrial geomechanical/geotechnical engineering challenges, e.g., in optimising foundations or tunnels to mitigate risks of structural failure, and even extra-terrestrial challenges relating to mechanical behaviour of soils at lunar/martian landing sites. In a more general sense, the research will have impact on more diverse areas involving granular mechanics including industrial powder processing, pharmaceutical pill manufacturing and food science, amongst others.
Recent publications (in the context of the above mentioned projects on granular mechanics)
- see here for full publication list (and below for earlier publications on granular mechanics.
- Hurley, R.C., Hall, S.A., Andrade, J.E. and Wright, J.. 2016, Quantifying Interparticle Forces and Heterogeneity in 3D Granular Materials, Phys. Rev. Lett. 117, 098005
- see also a "synopsis" in Physics magazine
- Hall, S.A. and Wright, J., 2015, Three-dimensional experimental granular mechanics, Géotechnique Letters, 5, 236–242
- Hall, S.A., and Wright, J., 2014, Characterisation of 3D force transmission in real granular media, Proc. 16th International Conference on Experimental Mechanics, 7-11 July, 2014, of Cambridge UK
"Historical" publications on granular mechanics by S. Hall and co-authors (work prior to, but associated with, the above mentioned projects)
- Andò , E., Viggiani, G., Hall, S.A., and Desrues, J., 2013, Experimental micro-mechanics of granular media studied by x-ray tomography: recent results and challenges, Géotechnique Letters 3, 142–146
- Andò, E., Hall, S.A., Viggiani, G., Desrues, J. and Bésuelle, P., 2012, Experimental micromechanics: grain-scale observation of sand Deformation, Géotechnique Letters, 2, 107–112
- Hall, S.A., Desrues, J., Viggiani, G., Bésuelle, P., and Andò, E., 2012, Experimental characterisation of (localised) deformation phenomena in granular geomaterials from sample down to inter- and intra-grain scales, in Full field measurements and identification in Solid Mechanics, Procedia IUTAM, 4, 54–65
- Andò, E., Hall, S.A., Viggiani, G., Desrues, J. and Bésuelle, P., 2012, Grain scale experimental investigation of localised deformation in sand: a discrete particle tracking approach, Acta Geotechnica, 7, 1-13.
- Hall, S.A., Wright, J., Pirling, T., Andò, E., Hughes, D.J. and Viggiani, G., 2011, Can intergranular force transmission be identified in sand? First results of spatially-resolved neutron and x-ray diffraction, Granular Matter, 13, 251-254.
- Tagliaferri, F., Waller, J., Andò, E., Hall, S.A., Viggiani, G., Bésuelle, P. and De Jong, J.T., 2011, Observing strain localisation processes in bio-cemented sand using x-ray imaging, Granular Matter, 13, 247-250.
- Hall, S.A., Bornert M., Desrues J., Pannier Y., Lenoir N., Viggiani, G., Bésuelle, P., 2010, Discrete and Continuum analysis of localised deformation in sand using X-ray micro CT and Volumetric Digital Image Correlation, Géotechnique, 60, 315 –322.
- Hall, S.A., Muir Wood, D., Ibraim, E. and Viggiani, G., 2010, Localised deformation patterning in 2D granular materials revealed by digital image correlation, Granular Matter, 12, 1-14.