Fracture analysis in quasi-brittle materials via an adaptive cohesive interface model

Abstract

This study presents an advanced numerical model for simulating fracture propagation in heterogeneous materials utilizing an inter-element cohesive zone approach combined with the Arbitrary Lagrangian-Eulerian (ALE) kinematic description. In particular, the proposed methodology uses the moving mesh technique to adjust the computational domain so that the crack segment, selected once a suitable stress criterion for fracture onset is satisfied, is aligned to the computed crack propagation direction. Subsequently, a zero-thickness interface cohesive element, equipped with a traction-separation law, is inserted on-the-fly along the crack segment to describe the nonlinear fracture process. Despite the recent fracture models, the proposed framework allows the multiple crack onset and propagation without requiring mesh updated procedures and sensibly reduces the well-known mesh dependency issues of alternative discrete fracture approaches. Numerical analyses have been performed to validate the proposed model, involving quasi-brittle heterogeneous materials like fiber-reinforced concrete subjected to different loading conditions. Comparisons with available experimental and numerical results have highlighted the effectiveness and reliability of the proposed model in the prediction of fracture in quasi-brittle materials.