Issue 47

A. Spagnoli et alii, Frattura ed Integrità Strutturale, 47 (2019) 394-400; DOI: 10.3221/IGF-ESIS.47.29 400 C ONCLUSIONS n experimental campaign on the fracture behavior of Carrara marble under monotonic and cyclic loading has been carried out. The results under monotonic loading show a well-known quasi-brittle behavior of the material, which requires for instance a two-parameter approach to correctly estimate fracture toughness. The results under cyclic loading allow us to estimate the material parameters governing the fatigue crack growth. Also, such results allow an attempt to estimate a fatigue limit in terms of SIF threshold. A comparison of experimental monotonic results with those of a numerical model based on a cohesive crack approach shows a good correlation. Finally, the numerical results permit to give an insight on the correlation between FPZ and fatigue threshold conditions. Further investigation is needed to fully understand the experimental observation under cyclic temperature of the different behavior of marble depending on the microstructural texture of calcite grains (see xenoblastic and homoblastic types of marble) and in turns on the roughness features of intergranular cracking profiles. R EFERENCES [1] Ferrero, A.M., Migliazza, M., Spagnoli, A. Theoretical modelling of bowing in cracked marble slabs under cyclic thermal loading (2009) Construction and Building Materials, 23 (6), pp. 2151-2159. [2] Spagnoli, A., Ferrero, A.M., Migliazza, M. A micromechanical model to describe thermal fatigue and bowing of marble (2011) International Journal of Solids and Structures, 48 (18), pp. 2557-2564. [3] Spagnoli, A., Carpinteri, A., Ferretti, D., Vantadori, S. An experimental investigation on the quasi-brittle fracture of marble rocks (2016) Fatigue and Fracture of Engineering Materials and Structures, 39 (8), pp. 956-968. [4] Migliazza, M., Ferrero, A.M., Spagnoli, A. Experimental investigation on crack propagation in Carrara marble subjected to cyclic loads (2011) International Journal of Rock Mechanics and Mining Sciences, 48 (6), pp. 1038-1044. [5] Cendon, D. A., Torabi, A. R., Elices, M. Fracture assessment of graphite V - notched and U - notched specimens by using the cohesive crack model (2015) Fatigue and Fracure of Engineering Materials and Structures, 38 (5), pp. 563-573. [6] Jenq, Y. and Shah, S. P. (1985) Two parameter fracture model for concrete. J. Eng. Mech., 111, 1227–1241. [7] Carpinteri, A., Berto, F., Fortese, G., Ronchei, C., Scorza, D., Vantadori, S. (2017), Modified two-parameter fracture model for bone. Engineering Fracture Mechanics, 174, 44–53, DOI: 10.1016/j.engfracmech.2016.11.002. [8] Carpinteri, A., Fortese, G., Ronchei, C., Scorza, D., Vantadori, S. (2017), Mode I fracture toughness of fibre reinforced concrete, Theoretical and Applied Fracture Mechanics, 91, 66-75, DOI: 10.1016/j.tafmec.2017.03.015. [9] Vantadori, S., Carpinteri, A., Guo, L.-P., Ronchei, C., Zanichelli, A. (2018), Synergy assessment of hybrid reinforcements in concrete, Composites Part B: Engineering, 147, 197-206, DOI: 10.1016/j.compositesb.2018.04.020. [10] Bazant, Z. P. (1996) Analysis of work-of-fracture method for measuring fracture energy of concrete. J. Eng. Mech. ASCE, 122, 138–144. [11] Fleck, N. A., K. J. Kang, and M. F. Ashby. (1994). Overview No. 112: The cyclic properties of engineering materials. Acta Metallurgica et Materialia 42(2), pp. 365-381. [12] Hillerborg, A., Modéer, M., and Petersson, P. (1976). Analysis of crack formation and crack growth in concrete by means of fracture mechanics and finite elements, Cement and Concrete Res. 6. [13] Sancho, J.M., Planas, J., Cendón, D.A., Reyes, E., Gálvez, J.C. (2007). An embedded crack model for finite element analysis of concrete fracture. Eng. Fract. Mech., 74, pp. 75-86. [14] Cendón, D.A., Torabi, A.R. and Elices, M. (2015). Fracture assessment of graphite V- and U- notched specimens by using the cohesive crack model. Fat. and Fract. of Eng. Mats and Structures, 38-5, pp. 563-573. [15] Bazant, Z.P. and Planas, J. (1998). Fracture and size effect in concrete and other quasibrittle materials. CRC Press. Boca Raton, Florida. [16] Guinea, G.V., Planas, J. and Elices, M. (1994). A general bilinear fit for the softening curve of concrete. Materials and structures 27 (2), pp. 99-105. [17] Dugdale, D.S. (1960), Yielding of steel sheets containing slits. J. Mech. Phys. Solids, 8, pp. 100. [18] Cendón, D.A., Jin, N., Liu, Y., Berto, F. and Elices, M. (2017). Numerical Assessment of Gray Cast Iron Notched Specimens by Using a Triaxiality-Dependent Cohesive Zone Model. Theoretical and Applied Fracture Mechanics 90, pp. 259-267. A