A novel cohesive crack model for concrete based on linear displacement patterns in the fracture process zone

Abstract

The evolution of the fracture process zone (FPZ) in concrete beams of various sizes subjected to three-point bending tests was quantified using digital image correlation techniques. Based on the full-field deformation data, the FPZ length and crack-opening displacement (COD) were obtained. The results indicate that the COD exhibits a linear variation along the FPZ. Leveraging this linear COD profile alongside the tensile softening curve of concrete, a novel analytical cohesive-crack model was developed. This model effectively replicates the nonlinear fracture response of concrete under external loading conditions. Furthermore, it elucidates the propagation behavior of the FPZ and accounts for the size effect observed in the nonlinear fracture of concrete. The findings of this research can serve as a valuable reference for simulating the nonlinear fracture behavior of quasi-brittle materials, including concrete and rock.