Finite element analysis of concrete cracking: a comparative study between a diffuse interface model and an embedded crack model

Abstract

The accurate analysis of cracking phenomena in the concrete structures has been a research topic of growing interest over the past few decades, with notable developments in the modeling techniques based on either smeared or discrete fracture approaches. The well-known cohesive zone models, belonging to discrete fracture approaches, are commonly judged as very effective for accurately representing the real crack pattern in quasi-brittle materials. The present work deals with comparing two different finite element-based cohesive fracture models: (i) a novel diffuse interface model, and (ii) an existing embedded crack model, based on an inter- and intra- element fracture approach, respectively. The first one relies on an intrinsic cohesive formulation by which the damage process inside the material is represented as a collection of imperfect interfaces randomly placed at the internal boundaries of a finite element mesh. The second one is based on a strong discontinuity approach according to which the crack is modeled as a discontinuity embedded into the displacement field of a standard continuum, allowing concrete cracking along nonprescribed paths to be correctly simulated. Cracking behavior in concrete specimens subjected to general loading conditions has been simulated by these two models and a detailed comparison between the numerical results is provided. Finally, a critical discussion regarding of computational efficiency and numerical accuracy highlights the efficacy of the newly proposed diffuse interface model.