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Tailored extended finite - element model for predicting crack propagation and fracture properties within idealized and digital cementitious material samples / Kenny Ng in Journal of engineering mechanics, Vol. 138 N° 1 (Janvier 2012) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 138 N° 1 (Janvier 2012) . - pp.89-100 Titre : Tailored extended finite - element model for predicting crack propagation and fracture properties within idealized and digital cementitious material samples Type de document : texte imprimé Auteurs : Kenny Ng, Auteur ; Qingli Dai, Auteur Année de publication : 2012 Article en page(s) : pp.89-100 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Heterogeneous  cement-based  materials  Extended  finite  element  model  Micromechanics  Compact  tension  test  Single-edge  notched  beam  test  Damage  evolution  Fracture  properties Résumé : This paper presents a tailored extended finite-element model (XFEM) to predict crack propagation and fracture properties within idealized and digital cementitious material samples. The microstructure of the idealized cement-based materials includes the cement paste, particles, and interfacial boundaries. The tailored XFEM was developed to allow crack propagation within finite elements by using discontinuous enrichment functions and level-set methods. The Heaviside jump and the elastic asymptotic crack-tip enrichment functions were used to account for the displacement discontinuity across the crack-surface and around the crack-tip. The maximum fracture energy release rate was used as a criterion for determining the crack growth. The shielding effects within the interfacial zone were addressed with a numerical search scheme. The tailored XFEM was implemented with a MATLAB program to simulate the compact tension (CT) and the single-edge notched Beam (SEB) tests. For a homogeneous CT testing sample, the XFEM prediction on stress intensity factors was verified with the fracture mechanics analysis. The idealized samples of cement-based materials were generated with varied microstructures, including particle locations, orientations, and shape factors. The tailored XFEM was applied to investigate the effects of these microparameters on the fracture patterns of the idealized samples under CT loading. The XFEM simulation was also conducted on a homogeneous offset-notched SEB sample to predict the mixed-mode crack propagation. The predicted crack path matches well with refined cohesion fracture modeling from a recent study. Further validation of the tailored XFEM was conducted with fracture simulation of a digital SEB sample generated from the actual tested specimen. The predicted crack path was favorably compared with the fracture pattern of the tested concrete specimen with a middle notch. These simulation results indicated that the tailored XFEM has the ability to accurately predict the crack propagation and fracture properties within idealized and digital cementitious material samples. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000316 [article] Tailored extended finite - element model for predicting crack propagation and fracture properties within idealized and digital cementitious material samples [texte imprimé] / Kenny Ng, Auteur ; Qingli Dai, Auteur . - 2012 . - pp.89-100. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 138 N° 1 (Janvier 2012) . - pp.89-100 Mots-clés : Heterogeneous  cement-based  materials  Extended  finite  element  model  Micromechanics  Compact  tension  test  Single-edge  notched  beam  test  Damage  evolution  Fracture  properties Résumé : This paper presents a tailored extended finite-element model (XFEM) to predict crack propagation and fracture properties within idealized and digital cementitious material samples. The microstructure of the idealized cement-based materials includes the cement paste, particles, and interfacial boundaries. The tailored XFEM was developed to allow crack propagation within finite elements by using discontinuous enrichment functions and level-set methods. The Heaviside jump and the elastic asymptotic crack-tip enrichment functions were used to account for the displacement discontinuity across the crack-surface and around the crack-tip. The maximum fracture energy release rate was used as a criterion for determining the crack growth. The shielding effects within the interfacial zone were addressed with a numerical search scheme. The tailored XFEM was implemented with a MATLAB program to simulate the compact tension (CT) and the single-edge notched Beam (SEB) tests. For a homogeneous CT testing sample, the XFEM prediction on stress intensity factors was verified with the fracture mechanics analysis. The idealized samples of cement-based materials were generated with varied microstructures, including particle locations, orientations, and shape factors. The tailored XFEM was applied to investigate the effects of these microparameters on the fracture patterns of the idealized samples under CT loading. The XFEM simulation was also conducted on a homogeneous offset-notched SEB sample to predict the mixed-mode crack propagation. The predicted crack path matches well with refined cohesion fracture modeling from a recent study. Further validation of the tailored XFEM was conducted with fracture simulation of a digital SEB sample generated from the actual tested specimen. The predicted crack path was favorably compared with the fracture pattern of the tested concrete specimen with a middle notch. These simulation results indicated that the tailored XFEM has the ability to accurately predict the crack propagation and fracture properties within idealized and digital cementitious material samples. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000316