Coupling of discrete crack and continuous damage model to describe the complete process of concrete fracture

The concrete fracture process is an extensively studied theme that encompasses different areas. Different strategies for modeling concrete cracking have arisen in the past few years, and the subject remains challenging. This paper aims to investigate the behavior of concrete from a diffuse degradation in the fracture process zone (FPZ) to a discontinuity due to a crack. This scenario proposes a modeling strategy based on coupling a nonlocal continuum damage model with a discrete crack model. The discrete crack model adopts the technique of nodal duplication combined with the collocation points to evaluate crack initiation and propagation and perform the mesh redefinition. The nucleation is based on critical damage announced by the constitutive model, which is employed to describe the material degradation process. The strategy is advantageous due to the well-established theoretical bases, opening the way to new improvements and applications in conventional structures or other approaches such as geotechnics, brittle fracture, and ductile materials.