PSI - Issue 2_A

Jan Klusák et al. / Procedia Structural Integrity 2 (2016) 1912–1919 J. Klusák / StructuralIntegrity Procedia 00 (2016) 000–000

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aggregate. For this reason they are evaluated by means of the bi-material notch model and by using generalized fracture mechanics approaches. The results are presented in terms of critical applied stress under which further crack propagation occurs. Two modes of crack propagation are evaluated, namely crack propagation in the direction of the global maximum of average tangential stress and crack kink and propagation into the material 2 in the direction parallel to the bi-material interface (this direction corresponds to the local maximum of average tangential stress).

Fig. 5. Critical applied stress  crit ( E 1 / E 2 )

It is shown that in the studied cases the critical applied stress and the mode of further crack propagation depend mainly on fracture toughness of a matrix and aggregate. With respect to the reference case of crack propagation in a homogeneous matrix, the corner of tough aggregate (granite, basalt etc.) contributes significantly to toughening mechanisms of silicate based composites. Acknowledgements This research has been financially supported by the Ministry of Education, Youth and Sports of the Czech Republic under the project CEITEC 2020 (LQ1601). The authors would like to thank the Czech Science Foundation for financial support through the Grant 16/18702S. References Erdogan, F., Sih, G.C., 1963. On the crack extension in plates under plane loading and transversal shear. Int J Basic Engineering 85(4), 519-527. Klusák, J., Profant, T., Kotoul, M., 2008. A comparison of two direct methods of generalized stress intensity factor calculations of bi-material notches, Key Eng Mater. 385-387, 409-412. Klusák, J., Knésl, Z., 2010. Reliability assessment of a bi-material notch: Strain energy density factor approach, Theor Appl Fract Mech 53, 89– 93. Klusák, J., Profant, T., Knésl, Z., Kotoul, M., 2013. The influence of discontinuity and orthotropy of fracturetoughness on conditions of fracture initiation in singular stress concentrators, Engineering Fracture Mechanics 110, 438–447. Knésl, Z., 1991. A criterion of V-notch stability. International Journal of Fracture 48(4), R79 – R83. Leguillon, D., 2002. Strength or toughness? A criterion for crack onset at a notch, Eur J Mech A-Solid. 21(1), 61-72. Ping, X.C., Chen, M.C., Xie, J.L., 2008. Singular stress analyses of V-notched anisotropic plates based on a novel finite element method. Eng Fract Mech. 75, 3819–3838. Profant, T., Ševeček, O., Kotoul, M., 2008 . Calculation of K-factor and T-stress for cracks in anisotropic bimaterials, Eng Fract Mech. 75, 3707–3726. Qian, Z.Q., Akisania, A.R., 1999. Wedge corner stress behaviour of bonded dissimilar materials, TheorAppl Fract Mech. 32, 209-22. Taylor, D., 2007. The theory of critical distances. Eng Fract Mech. 75, 1696-1705. Williams, M.L., 1957. On the stress distribution at the base of stationary crack. Int J Appl Mech. 24, 109-14.