Modelling the evolution of fracture process zone considering strain rate effect

This paper highlights the importance of strain rate effects at the meso scale of the Fracture Process Zone (FPZ) on macro responses through a numerical approach employing a new coupled damage-plasticity model for the simulation of a three-point bending test on quasi-brittle materials using the SPH (Smoothed Particle Hydrodynamics). The strain rate effect is handled by enhancing the flow rules with a Perzyna-type rate-dependent formulation. This enhancement improves the capability of the model to describe constitutive behaviour under varying strain rates, with results showing that the rate-dependent formulation can capture the increase in flexural strength at higher loading velocities. While both rate-dependent and rate-independent models lead to comparable strain rates inside the FPZ as applied loading velocity changes, the peak loads vary significantly. This simulation result highlights strong dynamic effects inside the FPZ that can influence the macro response, even in quasi-static loading conditions, encouraging future experimental work to investigate this connection.