Micromechanics-Driven Variational Method for Diffuse-to-Localised Fracture in Quasi-Brittle Solids

. A novel multiscale variational method for modelling fracture propagation is proposed. The method employs strong discontinuity kinematics enhancement, enabling macroscopic cracks to be modelled explicitly, while minimum remeshing is ensured. In addition, the response of quadrature points in the bulk is up-scaled using a Micromechanical continua, which enables the evolution of directional micro-defects (e.g. microcracks) without venturing into prohibitive computational burden. Noticeably, the method allows the Micromechanical continua to interact with macroscopic cracks. The framework is conveniently formulated as a variational setting to provide a minimum energy solution. The new computational framework has been found to diagnose realistic failure mechanisms in quasi-brittle materials.