Diffuse versus localized failure: Assessing the impact of concrete quality

Abstract

In this work, the influence of the concrete quality on the occurrence of both diffuse and localized failure modes in the form of discontinuous bifurcation is investigated. Based on the non-linear constitutive model for concrete of arbitrary strength capabilities proposed by the authors, theso-called Performance Dependent Model (PDM), failure conditions are assessed by numerical and geometrical procedures, through the proposition of failure indicators and localization ellipses, respectively. Numerical results, on the one hand, confirm the capability of the PDM to capture the expected failure modes and, on the other hand, demonstrate relevant differences between normal and high performance concrete behaviors regarding the location of transition points between ductile and brittle failure, the orientation of discontinuity directions, and the critical stress states corresponding to the onset of material instabilities and discontinuous bifurcation.