From diffuse damage to sharp cohesive cracks: A coupled XFEM framework for failure analysis of quasi-brittle materials

摘要: Abstract Failure of quasi-brittle materials is governed by crack formation and propagation which can be characterized two phases: (i) diffuse material degradation process with initial (ii) severe localization damage leading to the large cracks fracture. While continuum mechanics provides an excellent framework describe first failure phase, it unable represent discontinuous displacement fields. In sharp contrast, cohesive zone models are poorly suited for describing but accurately resolve discrete cracks. this manuscript, we propose a coupled continuous/discontinuous approach model phases in coherent way. The proposed involves integral-type nonlocal extrinsic interface model. transition from macroscopic made through equivalent thermodynamic established multidimensional settings, dissipated energy computed numerically weakly matched. method implemented within extended finite element framework, allows without remeshing. A few benchmark problems involving straight curved investigated demonstrate applicability robustness XFEM cohesive-damage approach. Force–displacement responses, as well predicted paths, presented shown close agreement available experimental data. Furthermore, found insensitive various threshold values damage–crack transition, yielding energetically consistent results.