INTECIN   20395
INSTITUTO DE TECNOLOGIAS Y CIENCIAS DE LA INGENIERIA "HILARIO FERNANDEZ LONG"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Fracture energy-based constitutive theory for failure behavior of arbitrary strength concrete
Autor/es:
FOLINO, P; ETSE, G
Lugar:
Minneapolis
Reunión:
Congreso; USNCCM 11th - US National Congress on Computational Mechanics; 2011
Institución organizadora:
US Association for Computational Mechanics
Resumen:
The significant progress made in concrete technology in the past decade allowed the fabrication of concrete characterized with very high strength properties. Consequently, concrete materials presently involve a very wide spectrum of strength capacities and qualities. Their failure behaviors exhibit very different features. While normal strength concrete (NSC) is characterized by reduced compressive strength, the tensile strength vs. compressive strength ratio and the post-peak ductility are clearly higher than in case of high strength concrete (HSC). Other relevant material parameters like the internal friction, the fracture energy release in mode I and II type of fracture, the dependence of the strength capacity on the acting confining pressure and the elastic module also depend strongly on the involved material quality, i.e. on the uniaxial compressive strength. The experimental evidence demonstrates the strong dependence of concrete failure behavior on the involved material quality or material strength property. When dealing with concrete structures, their failure behaviors are also strongly sensitive to the particular quality and strength properties of the constitutive material. Predictive analysis of concrete structure failure processes require reliable constitutive model that are able to reproduce the fundamental differences of the mechanical response behavior of concretes characterized by different strength properties. Although a significant progress was made in the last two decades regarding the formulation of constitutive models for concrete, most of the proposals refer to NSC. Then, they predictive capability of failure behavior of HSC is reduced as they are not able to reproduce the significant changes in the relevant material properties with the involved quality. In this work, a performance dependent constitutive model for concretes of arbitrary strengths is presented. The model is based on the flow theory of plasticity and takes into account fracture energy concepts for the formulation of the softening law. The maximum strength surface of the model and the hardening/softening evolution laws are described in terms of the so-called concrete performance parameter. This parameter is introduced to evaluate concrete quality in terms of uniaxial strength and of the water/binder ratio, as proposed by the authors [Folino, Etse & Will 2009]. The pre and post-peak behavior of concrete are described by means of non-uniform hardening and isotropic softening formulations. Volumetric dilatancy of concretes of arbitrary strengths is described by means of a volumetric non-associated flow rule that is also expressed in terms of the performance parameter. One of the relevant features of the proposed model is the C-1 continuous yield surface considered in the hardening regime that includes a cap. This allows to model and to evaluate the particular concrete non-linear behavior when subjected to pure hydrostatic loading. Once describing the most relevant equations of the proposed model numerical analyses are presented to illustrate model predictions of concrete failure behavior when different material qualities are involved. Finally, the attention focuses in the analysis of the localized failure indicator. Main objective is the evaluation of the location of the transition point between brittle and ductile failure modes as well as its dependence on the involved concrete quality.