Issue 41

J. Klon et alii, Frattura ed Integrità Strutturale, 41 (2017) 183-190; DOI: 10.3221/IGF-ESIS.41.25 190 one consists in multiplication of the value of the specific fracture energy (inputted into ATENA software) with the area of ligament. Three values of the specific fracture energy were considered: G f = 7; 70; 700 N/m. Specimens of four sizes with the same geometry proportions were assumed to reflect the impact of the size effect. The results obtained show a strong dependence of the amount of the dissipated energy during fracture on the value of the specific fracture energy considered for calculations. Similarly, a significant dependence of the maximum achieved loading force on the value of the specific fracture energy was observed. Therefore, it is crucial to set the proper value of the specific fracture energy when more complex fracture analyses need to be performed in order to avoid misleading results. Note that the authors intend to extend the study on the impact of the specific fracture energy value on the amount of the energy dissipated to the wedge splitting test geometry. A CKNOWLEDGEMENT his paper has been worked out under the project of the Czech Science Foundation (project No. 15-07210S). R EFERENCES [1] Bažant, Z.P., Kazemi, M.T., Size dependence of concrete fracture energy determined by RILEM work-of-fracture method, Int. J. Fract., 51(2) (1991) 121–138. [2] Elices, M., Guinea, G. V., Planas, J., Measurement of the fracture energy using three-point bend tests: part 3– Influence of cutting the P–δ tail, Mater. Struct., 25(6) (1992) 327–334. [3] Hu, X.-Z., Wittmann, F.H., Size effect on toughness induced by crack close to free surface. Engng. Fract. Mech., 65 (2000) 209–221. [4] Trunk, B., Wittmann, F.H., Influence of size on fracture energy of concrete, Mater. Struct, 36 (2001) 260–265. [5] Karihaloo, B.L., Abdalla, H.M., Imjai, T., A simple method for determining the true fracture energy of concrete. Mag. Concr. Res., 55 (2003) 471–481. [6] Duan, K., Hu, X.-Z., Wittmann, F.H., Boundary effect on concrete fracture and non-constant fracture energy distribution, Engng. Fract. Mech., 70 (2003) 2257–2268. [7] Bažant, Z.P., Yu, Q., Size effect in fracture of concrete specimens and structures: new problems and progress, in Li V.C. et al. (eds.), Proc. of the 5th international conference on fracture mechanics of concrete and concrete structures, Vail Colorado, USA, (2004) 153–162. [8] Hu, X.-Z., Duan, K., Size effect: Influence of proximity of fracture process zone to specimen boundary, Engng. Fract. Mech., 74 (2007) 1093–1100. [9] Yu, Q., Le, J., Hoover, C., Bažant, Z., Problems with Hu-Duan Boundary Effect Model and its comparison to Size- Shape Effect Law for quasi-brittle fracture, J. Eng. Mech., 89 (2010) 40–50. DOI: 10.1061/(ASCE)EM.1943-7889. [10] Cifuentes, H., Alcalde, M., Medina, F., Measuring the size-independent fracture energy of concrete, Strain, 49(1) (2013) 54–59. [11] Suresh, S., Fatigue of Materials, Cambridge University Press, (1998) 679. [12] Červenka, V., Jendele, L., Červenka, J., ATENA Program Documentation, Cervenka Consulting, Prague (2010). [13] Červenka, V., Červenka, J., Pukl, R., ATENA / A tool for engineering analysis of fracture in concrete, Sadhana- Adacemy Proceedings in Engineering Sciences, 27 (2002) 485–492. [14] Hoover, Ch.G., Bažant, Z.P., Vorel, J., Wendner, R., Hubler, M.H., Comprehensive concrete fracture tests: Description and results, Engng. Fract. Mech., 114 (2013) 92–103. [15] Klon, J., Veselý, V., Modelling of size and shape of damage zone in quasi-brittle notched specimens – analytical approach based on fracture-mechanical evaluation of loading curves, Frattura ed Integrità Strutturale, 39 (2017) 17–28. [16] Karihaloo, B.L., Fracture mechanics and structural concrete, Longman Sci. & Techn., New York (1995). T