Evolving material discontinuities: numerical modelling in the context of the strong discontinuity approach

J. OLIVER, A.E. HUESPE, S. BLANCO, D. LINERO

, Laboratoire de Mécanique des Contacts et des Solides (LaMCoS), Lyon, France

Simposio; Séminaire IUTAM. Discretisation Methods for evolving discontinuities; 2006

IUTAM

Displacement discontinuities are observed, at macroscopic scales, associated to material failure of brittle and quasi-brittle materials in terms of cracks, fractures, shear bands etc.. Therefore, modelling its formation, evolution and propagation is a goal of Computational Mechanics and, more specifically, of Computational Material Failure Mechanics. Numerical models aiming at capturing the way that material failure affects the reliability of structures, constructions or natural sites, should then consider the formation of those evolving discontinuities as the dominant phenomenon to be modelled. In recent years some new settings for displacement discontinuity modelling have appeared, involving some specific mechanical and numerical ingredients. The one termed strong discontinuity approach (SDA) is described in this work and specific branches, in terms of the mechanical ingredients are analyzed and compared, i.e.: - The Continuum Strong Discontinuity Approach (CSDA): Continuum (stress-strain) models, equipped with strain softening, are used to model material failure - The Discrete Strong Discontinuity Approach (DSDA): Specific traction-separation laws, equipped with displacement softening. Also possible alternatives in terms of numerical ingredients are studied, i.e.; - Finite elements with elemental embedded discontinuities (E-FEM): resorting to enriched deformation models with elemental support. - Finite elements with nodal based discontinuities (X-FEM): resorting to enriched deformation modes with nodal support. The relative behaviour and specific features of every alternative are analyzed via numerical simulations, and some additional techniques to overcome numerical difficulties are described as well. Open questions and future developments are finally tackled