tesi A. Caggiano.pdf - EleA@UniSA - Università degli Studi di Salerno

1.5. Objectives and activities of the thesisfracture energy-based plasticity formulation for plain mortar/concrete, the fiberbond-slip formulation and the fiber dowel action.• to validate the proposed constitutive theories above mentioned against experimentaldata extracted from the literature.• to evaluate the predictive capability the proposed interface constitutive theoryin numerical analysis of failure processes of FRCCs at both mesoscopic andmacroscopic levels of observation.• to deeply analyze the FRCC model prediction when different load scenarios andfiber quantities and qualities are considered.• to consider the composite model formulation, firstly employed into the interfaceproposal, for formulating and validating a simple non-linear cracked hinge modelaimed at predicting the structural post-cracking behavior of beams under fourpointbending.• to propose a continuum (smeared-crack) formulation, based on the non-linearmicroplane theory combined with the well-known “Mixture Theory” for describingthe failure behavior of FRCC.As aforementioned, a great part of this work deals with the formulation of a novel interfaceconstitutive model for discontinous fracture analysis of FRCC. For this purpose,FRCC can be regarded as a four-phase material (Figure 1.13), composed by:• (i ) coarse aggregates;• (i i ) plain mortar;• (i i i ) plain interfaces modeling the cementitious matrix-to-coarse aggregate interactionand• (i v) FRCC interfaces for the matrix-to-matrix crack modeling.In this methodology, only the coarse aggregates are explicitly discretized in the FE meshand embedded in a matrix phase representing the cementitious mortar plus smalleraggregates and fibers. In principle, an explicit meso-geometry permits to correctlymodel fracture and failure processes in concrete which are generally governed by themain composite heterogeneities.25