MODELLING OF FRACTURE PROCESS ZONE AND RELATED ENERGY DISSIPATION DURING QUASI-BRITTLE FRACTURE

The paper is focused on an estimation of the extent of the fracture process zone and the zone of cumulative damage evolving during tensile failure of structures made of quasi-brittle materials, e.g. cementitious composites. The zone is determined via a developed (semi-)analytical method based on a combination of multi-parameter linear elastic fracture mechanics, cohesive crack models and plasticity theory. Results of the method are verified by numerical simulations of three-point bending of notched beams using an academic computational code based on a discrete spring network (lattice-particle) model and programs based on continuum modelling (finite elements), both with implementation of the cohesive zone approach. Three materials differing in cohesive behaviour are considered in the study; apart from the classical quasi-brittle softening material also a quasi-ductile and a strain hardening ones are taken into account. Used simulation tools provide sound results, particularly in the case of the softening material. Moreover, significant potential of the developed modelling techniques is presented.