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Fracture mechanics of corrosion cracking in concrete by acoustic emission
Mechanisms of corrosion cracking in concrete are studied analytically and experimentally. The two-domain boundary element method (BEM) was applied to the mixed-mode crack extension based on the maximum circumferential stress criterion. Four crack patterns were generated by employing expansive agent. The traces of the surface crack, the diagonal crack, the horizontal crack and the internal crack in the arbitrary direction were analyzed by BEM and identified by Simplified Green's functions for Moment tensor Analysis (SiGMA) results with Virtual reality modeling language (VRML). It is confirmed that acoustic emission (AE) sources are clustered close to the final failure surface. According to the results of SiGMA, the number of AE events increases just before crack extension. Depending on the crack types, contributions of mode I and mode II are varied during crack extension. These results are summarized, as follows: 1. Micro-mechanics for nucleating the surface crack, the diagonal crack, the horizontal crack and the internal crack due to expansion of corrosive products were identified by SiGMA results. 2. The surface crack started to be initiated when the expansion pressure reach the peak. According to SiGMA results, mixed-mode and shear cracks were less active and tensile cracks mostly dominated. Mixed-mode cracks were a little more active than shear cracks at the post peak region. After the surface crack was nucleated, the diagonal crack or the internal crack was prone to extension. 3. For the diagonal crack, shear cracks were slightly dominant before the peak pressure. Then, both tensile and shear cracks became equally dominant at the post peak region. Eventually, tensile cracks dominated. 4. Mechanisms of corrosion cracking in concrete are dominantly of mode-I failure along with minor contribution of mixed-mode and mode-II. The results confirm a promise to identify the mechanisms of corrosion cracking in concrete by BEM and AE.
Fracture mechanics of corrosion cracking in concrete by acoustic emission
Mechanisms of corrosion cracking in concrete are studied analytically and experimentally. The two-domain boundary element method (BEM) was applied to the mixed-mode crack extension based on the maximum circumferential stress criterion. Four crack patterns were generated by employing expansive agent. The traces of the surface crack, the diagonal crack, the horizontal crack and the internal crack in the arbitrary direction were analyzed by BEM and identified by Simplified Green's functions for Moment tensor Analysis (SiGMA) results with Virtual reality modeling language (VRML). It is confirmed that acoustic emission (AE) sources are clustered close to the final failure surface. According to the results of SiGMA, the number of AE events increases just before crack extension. Depending on the crack types, contributions of mode I and mode II are varied during crack extension. These results are summarized, as follows: 1. Micro-mechanics for nucleating the surface crack, the diagonal crack, the horizontal crack and the internal crack due to expansion of corrosive products were identified by SiGMA results. 2. The surface crack started to be initiated when the expansion pressure reach the peak. According to SiGMA results, mixed-mode and shear cracks were less active and tensile cracks mostly dominated. Mixed-mode cracks were a little more active than shear cracks at the post peak region. After the surface crack was nucleated, the diagonal crack or the internal crack was prone to extension. 3. For the diagonal crack, shear cracks were slightly dominant before the peak pressure. Then, both tensile and shear cracks became equally dominant at the post peak region. Eventually, tensile cracks dominated. 4. Mechanisms of corrosion cracking in concrete are dominantly of mode-I failure along with minor contribution of mixed-mode and mode-II. The results confirm a promise to identify the mechanisms of corrosion cracking in concrete by BEM and AE.
Fracture mechanics of corrosion cracking in concrete by acoustic emission
Theoretische und experimentelle Untersuchung der korrosionsbedingten Rissbildung in Stahlbeton
Uddin, Farid A.K.M. (author) / Shigeishi, Mitsuhiro (author) / Ohtsu, Masayasu (author)
Meccanica ; 41 ; 425-442
2006
18 Seiten, 23 Bilder, 3 Tabellen, 9 Quellen
Article (Journal)
English
akustische Risssuche , Bruchmechanismus , elastische Bruchmechanik , Green-Funktion , Innenriss , mathematisches Modell , Oberflächenriss , Querriss , Rand-Elemente-Methode , Rissinitiierung , Simulationsversuch , Stahlbeton , Volumenvergrößerung , kinematische Analyse , Theorie-Experiment-Vergleich , Stahlkorrosion
Fracture mechanics and acoustic emission in concrete
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