No Cover Image

E-Thesis 790 views 320 downloads

The developments of multi-level computational methodologies for discrete element modelling of granular materials / Tingting Zhao

Swansea University Author: Tingting Zhao

DOI (Published version): 10.23889/Suthesis.52441

Abstract

Granular materials are prevalent in this world while their non-trivial behaviour, which may resemble solid, liquid and/or gas under di˙erent circumstances, is still poorly understood. The challenging mechanics and dynamics of granular materials combined with their ubiquity have made this topic espec...

Full description

Published: Swansea 2019
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa52441
Tags: Add Tag
No Tags, Be the first to tag this record!
first_indexed 2019-10-15T14:31:52Z
last_indexed 2023-01-11T14:29:35Z
id cronfa52441
recordtype RisThesis
fullrecord <?xml version="1.0"?><rfc1807><datestamp>2022-12-18T09:49:15.1194574</datestamp><bib-version>v2</bib-version><id>52441</id><entry>2019-10-15</entry><title>The developments of multi-level computational methodologies for discrete element modelling of granular materials</title><swanseaauthors><author><sid>d34e859269aea45f2c0122afe314fbf1</sid><ORCID>NULL</ORCID><firstname>Tingting</firstname><surname>Zhao</surname><name>Tingting Zhao</name><active>true</active><ethesisStudent>true</ethesisStudent></author></swanseaauthors><date>2019-10-15</date><abstract>Granular materials are prevalent in this world while their non-trivial behaviour, which may resemble solid, liquid and/or gas under di&#x2D9;erent circumstances, is still poorly understood. The challenging mechanics and dynamics of granular materials combined with their ubiquity have made this topic especially interesting to study. The discrete element method (DEM) is a reliable and e&#x2D9;ective numerical technique to model many scientific and engineering problems involving granular materials but it is still not a fully mature method. Considering the unique properties of granular materials and the inadequate features of the DEM, this thesis improves the current DEM from three di&#x2D9;erent aspects and scales.On the micro scale at the particle level, a novel contact model is developed by introducing the statistical Greenwood Williamson (GW) model which can consider the stochastic surface roughness of particles. Two non-dimensional forms of the original formulations are derived which can reduce the computational costs significantly. A Newton-Raphson based numerical solution is proposed which can solve the inter-dependence problem involved. A theoretical inconsistency of the classic GW model is deduced which leads to the development of the extended elastic GW (E-GW) model. An empirical normal contact law is obtained by the curve-fitting method and can be incorporated into the DEM code to conduct the one and three dimension compression tests. An extended elastic-plastic GW (EP-GW) model is developed to allow the plastic deformation at the asperities. Furthermore, the tangential contact model and thermal conductivity model are proposed.On the meso scale at the sample level, a new packing characterisation method is proposed based on the digitalised image matrix of a packing and the subsequent application of the principal component analysis (PCA) with which the configuration of the particle assemblies can be evaluated quantitatively. The procedures of the packing digitalisation and formation of packing image are established for both 2D and 3D cases. The obtained PCA results of the packing image matrix can be revealed by the proposed principal variance function (PVF) and dissimilarity coe&#xFF;cient (DC). The values of PVF and DC can indicate the magnitude of e&#x2D9;ects on a packing caused by the configuration randomness, the particle distribution, the packing density and the particle size distribution. The uniformity and isotropy of a packing can also be investigated by this PCA based approach.On the macro scale at the level of real industrial applications, the existing coarse graining methods are carefully analysed by the exact scaling law and the e&#x2D9;ective thermal properties of particulate phase change materials are derived by the homogenisation method. An enthalpy based discrete thermal modelling framework for particulate systems with phase change materials is developed which can consider both the heat conduction process and the phase change transition. This proposed methodology is assessed by solving a particle version of the classic one-phase Stefan melting problem. Additional numerical simulations are also conducted to illustrate the e&#x2D9;ectiveness of this modelling framework.</abstract><type>E-Thesis</type><journal/><volume/><journalNumber/><paginationStart/><paginationEnd/><publisher/><placeOfPublication>Swansea</placeOfPublication><isbnPrint/><isbnElectronic/><issnPrint/><issnElectronic/><keywords/><publishedDay>31</publishedDay><publishedMonth>12</publishedMonth><publishedYear>2019</publishedYear><publishedDate>2019-12-31</publishedDate><doi>10.23889/Suthesis.52441</doi><url/><notes>A selection of third party content is redacted or is partially redacted from this thesis.</notes><college>COLLEGE NANME</college><department>College of Engineering</department><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><degreelevel>Doctoral</degreelevel><degreename>Ph.D</degreename><apcterm/><funders/><projectreference/><lastEdited>2022-12-18T09:49:15.1194574</lastEdited><Created>2019-10-15T10:05:45.5550681</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Engineering and Applied Sciences - Uncategorised</level></path><authors><author><firstname>Tingting</firstname><surname>Zhao</surname><orcid>NULL</orcid><order>1</order></author></authors><documents><document><filename>0052441-15102019114007.pdf</filename><originalFilename>Zhao_Tingting_PhD_Thesis_Final_Redacted.pdf</originalFilename><uploaded>2019-10-15T11:40:07.9270000</uploaded><type>Output</type><contentLength>41875748</contentLength><contentType>application/pdf</contentType><version>Redacted version - open access</version><cronfaStatus>true</cronfaStatus><embargoDate>2019-10-14T00:00:00.0000000</embargoDate><copyrightCorrect>true</copyrightCorrect></document></documents><OutputDurs/></rfc1807>
spelling 2022-12-18T09:49:15.1194574 v2 52441 2019-10-15 The developments of multi-level computational methodologies for discrete element modelling of granular materials d34e859269aea45f2c0122afe314fbf1 NULL Tingting Zhao Tingting Zhao true true 2019-10-15 Granular materials are prevalent in this world while their non-trivial behaviour, which may resemble solid, liquid and/or gas under di˙erent circumstances, is still poorly understood. The challenging mechanics and dynamics of granular materials combined with their ubiquity have made this topic especially interesting to study. The discrete element method (DEM) is a reliable and e˙ective numerical technique to model many scientific and engineering problems involving granular materials but it is still not a fully mature method. Considering the unique properties of granular materials and the inadequate features of the DEM, this thesis improves the current DEM from three di˙erent aspects and scales.On the micro scale at the particle level, a novel contact model is developed by introducing the statistical Greenwood Williamson (GW) model which can consider the stochastic surface roughness of particles. Two non-dimensional forms of the original formulations are derived which can reduce the computational costs significantly. A Newton-Raphson based numerical solution is proposed which can solve the inter-dependence problem involved. A theoretical inconsistency of the classic GW model is deduced which leads to the development of the extended elastic GW (E-GW) model. An empirical normal contact law is obtained by the curve-fitting method and can be incorporated into the DEM code to conduct the one and three dimension compression tests. An extended elastic-plastic GW (EP-GW) model is developed to allow the plastic deformation at the asperities. Furthermore, the tangential contact model and thermal conductivity model are proposed.On the meso scale at the sample level, a new packing characterisation method is proposed based on the digitalised image matrix of a packing and the subsequent application of the principal component analysis (PCA) with which the configuration of the particle assemblies can be evaluated quantitatively. The procedures of the packing digitalisation and formation of packing image are established for both 2D and 3D cases. The obtained PCA results of the packing image matrix can be revealed by the proposed principal variance function (PVF) and dissimilarity coeÿcient (DC). The values of PVF and DC can indicate the magnitude of e˙ects on a packing caused by the configuration randomness, the particle distribution, the packing density and the particle size distribution. The uniformity and isotropy of a packing can also be investigated by this PCA based approach.On the macro scale at the level of real industrial applications, the existing coarse graining methods are carefully analysed by the exact scaling law and the e˙ective thermal properties of particulate phase change materials are derived by the homogenisation method. An enthalpy based discrete thermal modelling framework for particulate systems with phase change materials is developed which can consider both the heat conduction process and the phase change transition. This proposed methodology is assessed by solving a particle version of the classic one-phase Stefan melting problem. Additional numerical simulations are also conducted to illustrate the e˙ectiveness of this modelling framework. E-Thesis Swansea 31 12 2019 2019-12-31 10.23889/Suthesis.52441 A selection of third party content is redacted or is partially redacted from this thesis. COLLEGE NANME College of Engineering COLLEGE CODE Swansea University Doctoral Ph.D 2022-12-18T09:49:15.1194574 2019-10-15T10:05:45.5550681 Faculty of Science and Engineering School of Engineering and Applied Sciences - Uncategorised Tingting Zhao NULL 1 0052441-15102019114007.pdf Zhao_Tingting_PhD_Thesis_Final_Redacted.pdf 2019-10-15T11:40:07.9270000 Output 41875748 application/pdf Redacted version - open access true 2019-10-14T00:00:00.0000000 true
title The developments of multi-level computational methodologies for discrete element modelling of granular materials
spellingShingle The developments of multi-level computational methodologies for discrete element modelling of granular materials
Tingting Zhao
title_short The developments of multi-level computational methodologies for discrete element modelling of granular materials
title_full The developments of multi-level computational methodologies for discrete element modelling of granular materials
title_fullStr The developments of multi-level computational methodologies for discrete element modelling of granular materials
title_full_unstemmed The developments of multi-level computational methodologies for discrete element modelling of granular materials
title_sort The developments of multi-level computational methodologies for discrete element modelling of granular materials
author_id_str_mv d34e859269aea45f2c0122afe314fbf1
author_id_fullname_str_mv d34e859269aea45f2c0122afe314fbf1_***_Tingting Zhao
author Tingting Zhao
author2 Tingting Zhao
format E-Thesis
publishDate 2019
institution Swansea University
doi_str_mv 10.23889/Suthesis.52441
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Uncategorised{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Uncategorised
document_store_str 1
active_str 0
description Granular materials are prevalent in this world while their non-trivial behaviour, which may resemble solid, liquid and/or gas under di˙erent circumstances, is still poorly understood. The challenging mechanics and dynamics of granular materials combined with their ubiquity have made this topic especially interesting to study. The discrete element method (DEM) is a reliable and e˙ective numerical technique to model many scientific and engineering problems involving granular materials but it is still not a fully mature method. Considering the unique properties of granular materials and the inadequate features of the DEM, this thesis improves the current DEM from three di˙erent aspects and scales.On the micro scale at the particle level, a novel contact model is developed by introducing the statistical Greenwood Williamson (GW) model which can consider the stochastic surface roughness of particles. Two non-dimensional forms of the original formulations are derived which can reduce the computational costs significantly. A Newton-Raphson based numerical solution is proposed which can solve the inter-dependence problem involved. A theoretical inconsistency of the classic GW model is deduced which leads to the development of the extended elastic GW (E-GW) model. An empirical normal contact law is obtained by the curve-fitting method and can be incorporated into the DEM code to conduct the one and three dimension compression tests. An extended elastic-plastic GW (EP-GW) model is developed to allow the plastic deformation at the asperities. Furthermore, the tangential contact model and thermal conductivity model are proposed.On the meso scale at the sample level, a new packing characterisation method is proposed based on the digitalised image matrix of a packing and the subsequent application of the principal component analysis (PCA) with which the configuration of the particle assemblies can be evaluated quantitatively. The procedures of the packing digitalisation and formation of packing image are established for both 2D and 3D cases. The obtained PCA results of the packing image matrix can be revealed by the proposed principal variance function (PVF) and dissimilarity coeÿcient (DC). The values of PVF and DC can indicate the magnitude of e˙ects on a packing caused by the configuration randomness, the particle distribution, the packing density and the particle size distribution. The uniformity and isotropy of a packing can also be investigated by this PCA based approach.On the macro scale at the level of real industrial applications, the existing coarse graining methods are carefully analysed by the exact scaling law and the e˙ective thermal properties of particulate phase change materials are derived by the homogenisation method. An enthalpy based discrete thermal modelling framework for particulate systems with phase change materials is developed which can consider both the heat conduction process and the phase change transition. This proposed methodology is assessed by solving a particle version of the classic one-phase Stefan melting problem. Additional numerical simulations are also conducted to illustrate the e˙ectiveness of this modelling framework.
published_date 2019-12-31T04:04:48Z
_version_ 1763753369186336768
score 11.03559

Similar Items