PSI - Issue 42

V. Shlyannikov et al. / Procedia Structural Integrity 42 (2022) 714–721 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

720

7

Pure mode I Point 1

Initial pure mode II Point 1

Mixed mode with initial pure mode II Point 7

Fig. 7. The distribution of deformations along the crack extension obtained using VIC 3D and calculated by finite element method.

Conclusions Series of tests for CTS specimens under pure mode I, initial mode II and subsequent mixed mode was carried out. As a result of the experiments, curvilinear crack paths and contours of plastic deformation zones using DIC for specimens made of steel, titanium and aluminum alloys were obtained. By comparing the experimental and numerical data, the areas of mutual correspondence of the of plastic strain distributions obtained by digital image correlation and the finite element method are established. The range of values from 1∙10 -5 to 1∙10 -3 is found, within which the results of the classical HRR and gradient plasticity theories coincide. As the distance to the crack tip decreases, this trend is not observed. Acknowledgements The authors gratefully acknowledge the financial support of the Russian Science Foundation under the Project 20 19-00158. References Aoki, S., Kishimoto, K., Yoshida, T., Sakata, M., 1987. A finite element study of the near crack tip deformation of a ductile material under mixed mode loading. J. Mech. Phys. Solids 35, 431 – 55. Ayatollahi, M.R., Pavier, M.J., Smith, D.J., 1998. Determination of T-stress from finite element analysis for mode I and mixed mode I/II loading. Int. J. Fract. 91, 283 – 98. Ayatollahi, M.R., Zakeri, M., 2017. An improved definition for mode I and mode II crack problems. Eng. Fract. Mech. 175, 235 – 46. Fedotova, D., Khamidullin, R., Shlyannikov, V., 2022. Inversion Of Dislocation Densities Under Mixed Mode Fracture. Eng. Failure Analysis 138 (12), 106311. Fleck, N.A., Hutchinson, J.W., 1993. A phenomenological theory for strain gradient effects in plasticity. J. Mech. Phys. Solids 41 (12), 1825 – 1857. Fleck, N.A., Muller, G.M., Ashby, M.F., Hutchinson, J.W., 1994. Strain gradient plasticity: theory and experiment. Acta Metal. Mater. 42, 457 487. Fleck, N.A., Hutchinson, J.W., 1997. Strain gradient plasticity. Adv. Appl. Mech. 33, 295 – 361. Gao, H., Huang, Y., Nix, W.D., Hutchinson J.W., 1999. Mechanism-based strain gradient plasticity-I. Theory. J. Mech. Phys. Solids. 47, 1239 1263. Huang, Y., Qu, S., Hwang, K.C., Li, M., Gao, H., 2004. A conventional theory of mechanism-based strain gradient plasticity. Int. J. Plast. 20, 753 – 782. Martínez-Pañeda, E., Betegon, C., 2015. Modeling damage and fracture within strain-gradient plasticity. Int. J. Solids Struct. 59, 208 – 215. Martínez-Pañeda, E., Niordson, C.F., 2016. On fracture in finite strain gradient plasticity. Int. J. Plast. 80, 154-167. Martínez-Pañeda, E., Natarajan, S., Bordas, S., 2017. Gradient plasticity crack tip characterization by means of the extended finite element method. Comp. Mech. 59, 831 – 842.