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(305) Production(s) de KOB W.
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Origin of the non-linear elastic behavior of silicate glasses
Auteur(s): Zhang Z., Ispas S., Kob W.
(Article) Publié:
Acta Materialia, vol. 231 p.117855 (2022)
Texte intégral en Openaccess :
Ref HAL: hal-03690843_v1
Ref Arxiv: 2111.09549
DOI: 10.1016/j.actamat.2022.117855
WoS: WOS:000793420000002
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: For small tension the response of a solid to an applied stress is given by Hooke’s law. Outside this linear regime the relation between stress and strain is no longer universal and at present there is no satisfactory insight on how to connect for disordered materials the stress-strain relation to the microscopic properties of the system. Here we use atomistic computer simulations to establish this connection for the case of silicate glasses containing alkali modifiers. By probing how in the highly non-linear regime the stress-strain curve depends on composition, we are able to identify the microscopic mechanisms that are responsible for the complex dependence of stress on strain in these systems, notably the presence of an unexpected quasi-plateau in the tangent modulus. We trace back this dependence to the mobility of the modifiers which, without leaving their cage or modifying the topology of the network, are able to relieve the local stresses. Since the identified mechanism is general, the results obtained in this study will also be helpful for understanding the mechanical response of other disordered materials.
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Connecting packing efficiency of binary hard sphere systems to their intermediate range structure
Auteur(s): Yuan H., Zhang Z., Kob W., Wang Y.
(Article) Publié:
Physical Review Letters, vol. 127 p.278001 (2022)
Texte intégral en Openaccess :
Ref HAL: hal-03522429_v1
DOI: 10.1103/PhysRevLett.127.278001
Exporter : BibTex | endNote
Résumé: Using computed x-ray tomography we determine the three dimensional (3D) structure of binary hard sphere mixtures as a function of composition and size ratio of the particles q. Using a recently introduced four-point correlation function we reveal that this 3D structure has on intermediate and large length scales a surprisingly regular order, the symmetry of which depends on q. The related structural correlation length has a minimum at the composition at which the packing fraction is highest. At this composition also the number of different local particle arrangements has a maximum, indicating that efficient packing of particles is associated with a structure that is locally maximally disordered.
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Hunting for order in disordered systems
Auteur(s): Kob W.
Conférence invité: Colloque de lancement MIPS (Montpellier, FR, 2021-11-08)
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