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dc.contributor.authorMilkus, Rico
dc.date.accessioned2018-06-01T08:00:24Z
dc.date.available2018-06-01T08:00:24Z
dc.date.issued2018-09-30
dc.date.submitted2017-11-07
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/276423
dc.description.abstractThe recent development of a framework called non-affine lattice dynamics made it possible to calculate the elastic moduli of disordered systems directly from their microscopic structure and potential energy landscape at zero temperature. In this thesis different types of disordered systems were studied using this framework. By comparing the shear modulus and vibrational properties of nearest neighbour spring networks based on depleted lattices we were able to show that the dominating quantity of the system’s non-affine reorganisation during shear deformation is the affine force field. Furthermore we found that different implementation of disorder lead to the same behaviour at the isostatic point. Later we studied the effect of long range interaction in such depleted lattices with regard to spatial correlation local elasticity. We found that the implementation of long springs with decaying spring constant reproduced the spatial correlation observed in simulations of Lennard-Jones glasses. Finally we looked at simple freely rotating polymer model chains by extending the framework to angular forces and studied the dependence of the shear modulus and the vibrational density of states (VDOS) and length and bending stiffness of the chains. We found that the effect of chain length on the shear modulus and the vibrational density of states diminishes as it depends on the number of backbone bonds in the system. This number increases fast for short chains as many new backbone bonds are introduced but slows down significantly when the chain length reaches 50 monomers per chain. For the dependence on the bending stiffness we found a rich phenomenology that can be understood by looking at specific motions of the monomers relative the the chain geometry. We were able to trace back the different regimes of the VDOS to the simple model of the triatomic molecule. We also explored the limits of non-affine lattice dynamics when describing systems at temperatures T > 0 and gave an approximate solution for the shear modulus in this case.
dc.language.isoen
dc.rightsAll rights reserved
dc.rightsAll Rights Reserveden
dc.rights.urihttps://www.rioxx.net/licenses/all-rights-reserved/en
dc.subjectSoft Matter
dc.subjectStatistical Physics
dc.subjectPolymers
dc.subjectDefected Lattices
dc.subjectAmorphous solids
dc.subjectBoson Peak
dc.subjectDensity of States
dc.titleVibrational and mechanical properties of disordered solids
dc.typeThesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnameDoctor of Philosophy (PhD)
dc.publisher.institutionUniversity of Cambridge
dc.publisher.departmentDepartment of Chemical Engineering and Biotechnology
dc.date.updated2018-06-01T07:45:54Z
dc.identifier.doi10.17863/CAM.23726
dc.publisher.collegeWolfson
dc.type.qualificationtitlePhD in Statistical Physics
cam.supervisorZaccone, Alessio
cam.thesis.fundingfalse


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