A Multiscale Formulation for Cohesive Fracture Analysis

S. TORO; P.J SÁNCHEZ; P.J. BLANCO; A E. HUESPE; R. A. FEIJÓO

Paris

Conferencia; International Conference on Computational Modeling of Fracture and Failure (ECCOMAS thematic conference); 2015

ECCOMAS

The contribution presents a multiscale formulation addressed to evaluate cohesivemodel developed for fracture problems. The multiscale methodology can be categorizedas a semi-concurrent model, which uses a Representative Volume Element (RVE) to determine the cohesive forces at the macroscale.A variational multiscale formulation of the methodology has been previously presented by the authors ([1]). It has been shown there that the approach provides objectivemacroscale cohesive forces with respect to the microcell size, even after the onset of thestrain localization process observed at the macroscopic scale.Subsequently, the formulation has been generalized and improved in three aspects:1) cohesive surfaces are introduced at both scales of analysis; they are modeled withstrong discontinuity kinematics. New equations describing the insertion of the macroscale strains, into the micro-scale and the posterior homogenization procedure are considered ([2]); 2) extention of the formulation to model elastoplastic large deformation problems. 3) the computational procedure and numerical implementation have been adaptedto the improved formulation; The first and second points are emphasized here, while thethird one is briefly summarized in this contribution.The methodology is numerically assessed through a number of simulations. Typically,quasi-brittle concrete fracture problem are modeled. The numerical simulation adequatelycaptures the material degradation phenomenon at the mesostructural level, which inducesthe activation of cohesive surfaces at the structural scale.