Coupling by means of strong discontinuity approach between crack opening and gas permeability for concrete
Résumé
Due to industrial needs, one of the key issues nowadays is to develop numerical tools that are able to predict the leakage rate through a cracked concrete structure. This paper presents a validation of a numerical modelling of leakage rate through a mortar specimen in a splitting test versus experimental results. The mechanical state of the material is described by means of an enhanced non-local damage model which takes into account the stress state and provides a realistic damage field at failure. A semi discrete method based on a Strong Discontinuity (SD) approach is then considered to study the coupling between the mechanical state of the material and its permeability. This method consists in first determining the crack opening field in the crack surface, then coupling the permeability with the crack opening by means of a modified Poiseuille's law. The assessed crack openings given by the SD method is compared to Digital Image Correlation measurements. The comparison between the two shows that the assessed crack openings given by SD are in good agreement (the maximum relative error is less than 20%). The results of the coupling compared to experimental data show a good estimation of the structural permeability for high level of cracking. Moreover, for lower levels of cracking, low differences between numerical and experimental permeabilities are observed.
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