PSI - Issue 13

M.R. Ayatollahi et al. / Procedia Structural Integrity 13 (2018) 735–740

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Ayatollahi et al. / Structural Integrity Procedia 00 (2018) 000–000

5. Conclusions In the present research, the effect of geometric constraints on crack growth path under mode I loading was studied using two fracture criteria namely GSED and GMTS and the results were compared to the experimental results. The GSED criterion that includes both singular (i.e. K I , K II ) and first non-singular (i.e. T-stress) terms of stresses at the crack tip could provide considerably improved predictions for the experimentally obtained crack growth path. The crack growth deviation was found to be in direct relation with the amplitude of T-stress and the crack trajectories under mode-I loading were predicted very well by employing the GSED criterion, while the T-stress levels in the tested samples were lower than the critical values defined in GMTS criterion, therefore this criterion failed to predict the crack deviation in the studied geometries in this research. References Ayatollahi, M.R., Razavi, S.M.J., Rashidi Moghaddam, M., Berto, F., 2015. Mode I fracture analysis of Polymethylmetacrylate using modified energy—based models. Physical Mesomechanics 18(5), 53-62. Ayatollahi, M.R., Rashidi Moghaddam, M., Razavi, S.M.J., Berto, F., 2016. Geometry effects on fracture trajectory of PMMA samples under pure mode-I loading. Engineering Fracture Mechanics 163, 449–461. Betegon, C., Hancock, J.W., 1991. Two-parameter characterization of elastic-plastic crack-tip fields. Journal of Applied Mechanics 58, 104–110. Cotterell, B., 1966. Notes on the paths and stability of cracks. International Journal of Fracture Mechanics 2(3), 526-533. Larsson, S.G., Carlsson, A.J., 1973. Influence of non-singular stress and specimen geometry on small-scale yielding at each tip in elastic-plastic materials. Journal of Physics and solids 21, 263–277. Liu, S., Chao, Y.J., 2003. Variation of fracture toughness with constraint. International Journal of Fracture 124, 113–117. Razavi, S.M.J., Ayatollahi, M.R., Berto, F., 2018. A synthesis of geometry effect on brittle fracture. Engineering Fracture Mechanics 187, 94-102. Rice, J.R., 1974. Limitations to the small scale yielding for crack-tip plasticity. Journal of Mechanic of Physics and solids 22, 17–26. Smith, D.J., Ayatollahi, M.R., Pavier, M.J., 2001. The role of T-stress in brittle fracture for linear elastic materials under mixed-mode loading. Fatigue and Fracture of Engineering Materials and Structures 24, 137–150.