Consistent tangent formulation for 3D interface modeling of cracking/fracture in quasi-brittle materials

This paper presents a constitutive model for fracture simulations in quasi-brittle media within the framework of zero-thickness interface elements. The present formulation is a 3D extension of the earlier model developed by Carol et al. [I. Carol, P.C. Prat, C.M. López, A normal/shear cracking model. Application to discrete crack analysis, ASCE J. Engrg. Mech. 123 (8) (1997) 765–773] which may be used for macroscopic as well as meso- or micromechanical cracking studies of cement-based particle composites such as concrete. Aside from new aspects of the interface material model a perhaps more important feature of the paper is the development of a backward-Euler integration strategy which is combined with a local/global Newton solver based on a consistent tangent operator compatible with an adaptive substepping strategy. Finally, constitutive verification examples are presented, while three large-scale mesomechanical failure simulations illustrate the benefits of the new consistent tangent operator in the context of adaptive substepping.