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

Chapter 6. Structural scale failure analysis of FRCCthe one in blue outlines the interface in elastic regime (either in loading or unloadingstages). The cracked shape of the mesh at various strain stages is also represented: i.e.,at ɛ = 0.0045, ɛ = 0.0350 and ɛ = 0.0380.It can be observed that for plain concrete at fully localized (and ultimate) state (ɛ =0.0350), one localized and inclined band develops: it divides the specimen into twoblocks. The ultimate state for the SFRC with ρ f = 1.0% (attained with the strain ɛ =0.0350) is characterized by two inclined macro-cracks, which split the tests in threeparts. Then, when a very high fiber content is considered (SFRC with ρ f = 5.0%), aremarkable strain-hardening behavior is obtained and a deformed mesh with verydiffuse micro-crackings can be clearly observed in the right side of Figure 6.19.6.3.2 Compressive test at macroscopic scaleThe concrete panel with the geometry of 9 × 12 cm 2 (base and height, respectively)is considered in the analyses proposed in this section. The considered mesh for theanalyzed SFRC specimen is detailed in Figure 6.20. Iso-parametric triangular continuumelements (Figure 6.20a) are assumed as linear elastics. Then, interface elementsinserted between those continuum triangles are highlighted by thicker lines of Figure6.20b.abFigure 6.20: 2-D FE discretization for concrete specimens at macro-level: (a) continuumelements and (b) interfaces.134