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Mechanism behind the size effect phenomenon / Hu, Xiaozhi in Journal of engineering mechanics, Vol. 136 N° 1 (Janvier 2010) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 136 N° 1 (Janvier 2010) . - pp. 60-68 Titre : Mechanism behind the size effect phenomenon Type de document : texte imprimé Auteurs : Hu, Xiaozhi, Auteur ; Duan, Kai, Auteur Article en page(s) : pp. 60-68 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Size  effect  Cracking  Concrete  Ceramics. Résumé : Size effect (SE) on quasi-brittle fracture of concrete and concretelike heterogeneous materials has been commonly demonstrated by the influence of specimen size D on the transition from strength-dominant fracture to toughness-dominant fracture for geometrically similar specimens with a common initial-crack/specimen-size ratio, i.e., a0/D=constant. Under such a condition, size D appears to be the single controlling parameter for SE. In this study, we clarify that the primary source of quasi-brittle fracture, the presence of a large fracture process zone (FPZ) in front of a crack-tip, does not follow the condition of geometry similarity even for geometrically similar specimens. This suggests that the role of FPZ is not clearly explained for SE. Therefore, this study emphasizes the interaction between FPZ and the nearest specimen/structure boundary, and the consequent SE phenomenon. The deficiencies associated with the common SE models developed by Bazant and his coworkers are discussed through comparisons with the analysis on the boundary and FPZ interaction, or the boundary effect. It is shown that quasi-brittle fracture and the transition from strength-dominant fracture to toughness-dominant fracture can occur even if specimen/structure size D is constant, i.e., size D is not the dominant factor for SE. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/dbt/dbt.jsp?KEY=JENMDT&Volume=136&Issue=1 [article] Mechanism behind the size effect phenomenon [texte imprimé] / Hu, Xiaozhi, Auteur ; Duan, Kai, Auteur . - pp. 60-68. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 136 N° 1 (Janvier 2010) . - pp. 60-68 Mots-clés : Size  effect  Cracking  Concrete  Ceramics. Résumé : Size effect (SE) on quasi-brittle fracture of concrete and concretelike heterogeneous materials has been commonly demonstrated by the influence of specimen size D on the transition from strength-dominant fracture to toughness-dominant fracture for geometrically similar specimens with a common initial-crack/specimen-size ratio, i.e., a0/D=constant. Under such a condition, size D appears to be the single controlling parameter for SE. In this study, we clarify that the primary source of quasi-brittle fracture, the presence of a large fracture process zone (FPZ) in front of a crack-tip, does not follow the condition of geometry similarity even for geometrically similar specimens. This suggests that the role of FPZ is not clearly explained for SE. Therefore, this study emphasizes the interaction between FPZ and the nearest specimen/structure boundary, and the consequent SE phenomenon. The deficiencies associated with the common SE models developed by Bazant and his coworkers are discussed through comparisons with the analysis on the boundary and FPZ interaction, or the boundary effect. It is shown that quasi-brittle fracture and the transition from strength-dominant fracture to toughness-dominant fracture can occur even if specimen/structure size D is constant, i.e., size D is not the dominant factor for SE. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/dbt/dbt.jsp?KEY=JENMDT&Volume=136&Issue=1