Locally adaptive phase-field models and transition to fracture

This thesis proposes a new computational model for the efficient simulation of crack propagation, through the combination of a phase-field model in small subdomains around crack tips and a discontinuous model in the rest of the domain. The combined model inherits the advantages of both approaches. T...

Descripción completa

Detalles Bibliográficos
Autor: Muixí Ballonga, Alba
Tipo de recurso: tesis doctoral
Estado:Versión publicada
Fecha de publicación:2020
País:España
Institución:CBUC, CESCA
Repositorio:TDR. Tesis Doctorales en Red
OAI Identifier:oai:www.tdx.cat:10803/669747
Acceso en línea:http://hdl.handle.net/10803/669747
https://dx.doi.org/10.5821/dissertation-2117-330385
Access Level:acceso abierto
Palabra clave:Àrees temàtiques de la UPC::Matemàtiques i estadística
512
531/534
id ES_e4fdfef6be316e7b79ae697e9dcec8f2
oai_identifier_str oai:www.tdx.cat:10803/669747
network_acronym_str ES
network_name_str España
repository_id_str
dc.title.none.fl_str_mv Locally adaptive phase-field models and transition to fracture
title Locally adaptive phase-field models and transition to fracture
spellingShingle Locally adaptive phase-field models and transition to fracture
Muixí Ballonga, Alba
Àrees temàtiques de la UPC::Matemàtiques i estadística
512
531/534
title_short Locally adaptive phase-field models and transition to fracture
title_full Locally adaptive phase-field models and transition to fracture
title_fullStr Locally adaptive phase-field models and transition to fracture
title_full_unstemmed Locally adaptive phase-field models and transition to fracture
title_sort Locally adaptive phase-field models and transition to fracture
dc.creator.none.fl_str_mv Muixí Ballonga, Alba
author Muixí Ballonga, Alba
author_facet Muixí Ballonga, Alba
author_role author
dc.contributor.none.fl_str_mv Fernández Méndez, Sonia
Rodríguez-Ferran, Antonio
Universitat Politècnica de Catalunya. Facultat de Matemàtiques i Estadística
dc.subject.none.fl_str_mv Àrees temàtiques de la UPC::Matemàtiques i estadística
512
531/534
topic Àrees temàtiques de la UPC::Matemàtiques i estadística
512
531/534
description This thesis proposes a new computational model for the efficient simulation of crack propagation, through the combination of a phase-field model in small subdomains around crack tips and a discontinuous model in the rest of the domain. The combined model inherits the advantages of both approaches. The phase-field model determines crack propagation at crack tips, and the discontinuous model explicitly describes the crack elsewhere, enabling to use a coarser discretization and thus reducing the computational cost. In crack-tip subdomains, the discretization is refined to capture the phase-field solution, while in the discontinuous part, sharp cracks are incorporated into the coarse background discretization by the eXtended Finite Element Method (XFEM). As crack-tip subdomains move with crack growth, the discretization is automatically updated and phase-field bands are replaced by sharp cracks in the wake of cracks. The first step is the development of an adaptive refinement strategy for phase-field models. To this end, two alternatives are proposed. Both of them consider two types of elements, standard and refined, which are mapped into a fixed background mesh. In refined elements, the space of approximation is uniformly $h$-refined. Continuity between elements of different type is imposed in weak form to handle the non-conformal approximations in a natural way, without spreading of refinement nor having to deal with hanging nodes, leading to a very local refinement along cracks. The first adaptive strategy relies on a Hybridizable Discontinuous Galerkin (HDG) formulation of the problem, in which continuity between elements is imposed in weak form. The second one is based on a more efficient Continuous Galerkin (CG) formulation; a continuous FEM approximation is used in the standard and refined regions and, then, continuity on the interface between regions is imposed in weak form by Nitsche's method. The proposed strategies robustly refine the discretization as cracks propagate and can be easily incorporated into a working code for phase-field models. However, the computational cost can be further reduced by transitioning to the discontinuous in the combined model. In the wake of crack tips, the phase-field diffuse cracks are replaced by XFEM discontinuous cracks and elements are derefined. The combined model is studied within the adaptive CG formulation. Numerical experiments include branching and coalescence of cracks, and a fully 3D test.
publishDate 2020
dc.date.none.fl_str_mv 2020
2020
2020
dc.type.none.fl_str_mv info:eu-repo/semantics/doctoralThesis
info:eu-repo/semantics/publishedVersion
format doctoralThesis
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10803/669747
https://dx.doi.org/10.5821/dissertation-2117-330385
url http://hdl.handle.net/10803/669747
https://dx.doi.org/10.5821/dissertation-2117-330385
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv http://creativecommons.org/licenses/by/4.0/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by/4.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 136 p.
application/pdf
application/pdf
dc.publisher.none.fl_str_mv Universitat Politècnica de Catalunya
publisher.none.fl_str_mv Universitat Politècnica de Catalunya
dc.source.none.fl_str_mv TDX (Tesis Doctorals en Xarxa)
reponame:TDR. Tesis Doctorales en Red
instname:CBUC, CESCA
instname_str CBUC, CESCA
reponame_str TDR. Tesis Doctorales en Red
collection TDR. Tesis Doctorales en Red
repository.name.fl_str_mv
repository.mail.fl_str_mv
_version_ 1869422640392830976
spelling Locally adaptive phase-field models and transition to fractureMuixí Ballonga, AlbaÀrees temàtiques de la UPC::Matemàtiques i estadística512531/534This thesis proposes a new computational model for the efficient simulation of crack propagation, through the combination of a phase-field model in small subdomains around crack tips and a discontinuous model in the rest of the domain. The combined model inherits the advantages of both approaches. The phase-field model determines crack propagation at crack tips, and the discontinuous model explicitly describes the crack elsewhere, enabling to use a coarser discretization and thus reducing the computational cost. In crack-tip subdomains, the discretization is refined to capture the phase-field solution, while in the discontinuous part, sharp cracks are incorporated into the coarse background discretization by the eXtended Finite Element Method (XFEM). As crack-tip subdomains move with crack growth, the discretization is automatically updated and phase-field bands are replaced by sharp cracks in the wake of cracks. The first step is the development of an adaptive refinement strategy for phase-field models. To this end, two alternatives are proposed. Both of them consider two types of elements, standard and refined, which are mapped into a fixed background mesh. In refined elements, the space of approximation is uniformly $h$-refined. Continuity between elements of different type is imposed in weak form to handle the non-conformal approximations in a natural way, without spreading of refinement nor having to deal with hanging nodes, leading to a very local refinement along cracks. The first adaptive strategy relies on a Hybridizable Discontinuous Galerkin (HDG) formulation of the problem, in which continuity between elements is imposed in weak form. The second one is based on a more efficient Continuous Galerkin (CG) formulation; a continuous FEM approximation is used in the standard and refined regions and, then, continuity on the interface between regions is imposed in weak form by Nitsche's method. The proposed strategies robustly refine the discretization as cracks propagate and can be easily incorporated into a working code for phase-field models. However, the computational cost can be further reduced by transitioning to the discontinuous in the combined model. In the wake of crack tips, the phase-field diffuse cracks are replaced by XFEM discontinuous cracks and elements are derefined. The combined model is studied within the adaptive CG formulation. Numerical experiments include branching and coalescence of cracks, and a fully 3D test.En aquesta tesi es proposa un nou model computacional per a simular la propagació de fractures de manera eficient, a partir de la combinació d’un model de camp de fase en petits subdominis al voltant dels extrems de les fissures, i d’un model discontinu a la resta del domini. El model combinat manté els avantatges de tots dos tipus de model. El model continu determina la propagació de la fissura, i el model discontinu descriu explícitament la fissura en gairebé tot del domini, amb una discretització més grollera i el conseqüent estalvi en cost computacional. Als subdominis de camp de fase, la discretització es refina per tal d’aproximar bé la solució, mentre que a la part discontínua, les fissures s’incorporen a la discretització grollera a partir de l’eXtended Finite Element Method (XFEM). A mesura que les fissures es propaguen pel domini, la discretització s’actualitza automàticament i, lluny dels extrems, la representació suavitzada de les fissures a partir del camp de fase es reemplaça per una representació discontínua. El primer pas és definir una estratègia de refinament adaptatiu pels models continus de camp de fase. En aquesta tesi es proposen dues alternatives diferents. Totes dues consideren dos tipus d’elements, estàndards i refinats, que es mapen a la malla inicial. Als elements refinats, l’espai d’aproximació es refina uniformement. La continuïtat entre elements de tipus diferent s’imposa en forma feble per facilitar el tractament de les aproximacions no conformes, sense que s’escampi el refinament ni haver d’imposar restriccions als nodes de la interfície, donant lloc a un refinament molt localitzat. La primera estratègia adaptativa es basa en una formulació Hybridizable Discontinuous Galerkin (HDG) del problema, que imposa continuïtat entre elements en forma feble. La segona es basa en una formulació contínua més eficient; es fa servir una aproximació contínua del Mètode dels Elements Finits a les regions estàndards i refinades i, aleshores, a la interfície entre les dues regions s’imposa la continuïtat en forma feble amb el mètode de Nitsche. Les estratègies adaptatives refinen la discretització a mesura que les fissures es propaguen, i es poden afegir a un codi per a models de camp de fase de manera senzilla. No obstant, el cost computacional es pot reduir encara més fent servir el model combinat. Lluny dels extrems de les fissures, la representació suavitzada del camp de fase es substitueix per discontinuïtats en una discretització de XFEM, i els elements es desrefinen. El model combinat es formula a partir de l’estratègia adaptativa contínua. Els exemples numèrics inclouen bifurcació i coalescència de fissures, i un exemple en 3D.DOCTORAT EN MATEMÀTICA APLICADA (Pla 2012)Universitat Politècnica de CatalunyaFernández Méndez, SoniaRodríguez-Ferran, AntonioUniversitat Politècnica de Catalunya. Facultat de Matemàtiques i Estadística202020202020info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersion136 p.application/pdfapplication/pdfhttp://hdl.handle.net/10803/669747https://dx.doi.org/10.5821/dissertation-2117-330385TDX (Tesis Doctorals en Xarxa)reponame:TDR. Tesis Doctorales en Redinstname:CBUC, CESCAInglésL'accés als continguts d'aquesta tesi queda condicionat a l'acceptació de les condicions d'ús establertes per la següent llicència Creative Commons: http://creativecommons.org/licenses/by/4.0/http://creativecommons.org/licenses/by/4.0/info:eu-repo/semantics/openAccessoai:www.tdx.cat:10803/6697472026-06-14T12:46:07Z
score 15,300719

Similares en LA Referencia