Issue 41

J. Klon et alii, Frattura ed Integrità Strutturale, 41 (2017) 183-190; DOI: 10.3221/IGF-ESIS.41.25 183 Focused on Crack Tip Fields Impact of specific fracture energy investigated in front of the crack tip of three-point bending specimen J. Klon, J. Sobek, L. Malíková Brno University of Technology, Faculty of Civil Engineering, Institute of Structural Mechanics, Brno, Czech Republic klon.j@fce.vutbr.cz, http://orcid.org/0000-0002-9551-2185 sobek.j@fce.vutbr.cz, http://orcid.org/0000-0003-4215-1029 malikova.l@fce.vutbr.cz , http://orcid.org/0000-0001-5868-5717 S. Seitl Academy of Sciences of the Czech Republic, v. v. i., Institute of Physics of Materials, Brno, Czech Republic and Brno University of Technology, Faculty of Civil Engineering, Institute of Structural Mechanics, Brno, Czech Republic seitl@ipm.cz, http://orcid.org/0000-0002-4953-4324 A BSTRACT . Presented study is focused on the analysis of the dependence of the specific fracture energy value on the assumed work of fracture in three- point bending tests. Specimens of different sizes and relative notch lengths are assumed in this study, in order to take into account the size effect. The three-point bending test of cracked specimens is simulated numerically by means of commercial software based on the finite element method with implemented cohesive crack model. Three levels of the specific fracture energy are considered. K EYWORDS . Specific fracture energy; Finite element method; Work of fracture; Three-point bending test; Loading curve. Citation: Klon, J., Sobek, J., Malíková, L., Seitl, S., Impact of specific fracture energy investigated in front of the crack tip of three- point bending specimen, Frattura ed Integrità Strutturale, 41 (2017) 183-190. Received: 28.02.2017 Accepted: 15.04.2017 Published: 01.07.2017 Copyright: © 2017 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION valuation of the fracture parameters from experimental data measurement is usually accompanied by numerical calculations. This is unavoidable for example for the quasi-brittle materials, because the process of the failure is not uniform and depends on the test specimen size, shape and also on the boundary conditions during the test itself [1–10]. In the case of these materials, the so-called fracture process zone (FPZ) is situated near the crack tip but its size cannot be seen like in the case of the ductile materials (by range of the plastic zone) [11]. Therefore, some efforts have been made in order to identify the FPZ by means of numerical calculations and investigate its impact on the fracture E