Simulating the Fracture of Notched Mortar Beams through Extended Finite-Element Method and Peridynamics

Abstract

This paper simulates fracture in notched mortar beams under three-point bending using an extended finite-element method (XFEM) and peridynamics. A three-phase microstructure (i.e., cement paste, aggregates, and paste–aggregate interface) is used for the constitutive modeling of the mortar in order to obtain the elastic properties for simulation. In the XFEM approach, the simulated homogenized elastic modulus is used along with the total fracture energy of the cement mortar in a damage model to predict the fracture response of the mortar, including crack propagation and fracture parameters [Mode I stress intensity factor, KIC, and critical crack tip opening displacement (CTODC)]. The damage model incorporates a maximum principal stress-based damage initiation criterion and a traction-separation law for damage evolution. In the peridynamics approach, a bond-based model involving a prototype microelastic brittle (PMB) material model is used and implemented in LS-DYNA. The elastic properties and fracture energy release rates are used as inputs in the PMB model, along with the choice of peridynamic horizon size. Comparisons with experimental fracture properties (KIC, CTODC) and crack propagation paths from digital image correlation show that both approaches yield satisfactory results, particularly for KIC and crack extension. Thus, both methods can be adopted for fracture simulation of cement-based materials.