Advertisement

Crack-Tip Plastic Zone Size and Shape via DIC

  • G. L. G. Gonzáles
  • J. A. O. González
  • V. E. L. Paiva
  • J. L. F. Freire
Conference paper
Part of the Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)

Abstract

In this paper Digital Image Correlation (DIC) is used to characterize the crack-tip plastic zone size and shape under plane stress and plane strain situations. For that, two disk-shaped tension DC(T) specimens made of 1020 steel with thicknesses 2 and 30 mm were used in fatigue crack growth tests to simulated plane stress and plane strain conditions, respectively. Fatigue cracks were grown under quasi-constant ΔK (stress intensity factor range) and stress ratio (R) respectively equal to 20 MPa√m and 0.1. A single 100% overload was applied when the crack reached a crack length of 6 mm (i.e. total crack length/specimen width = 0.3). Experimental measurements of the monotonic plastic zone at different stages during overload application are compared with finite elements simulations to predict the size and shape of the crack-tip plastic zone. A detailed discussion is given based on the DIC measurements obtained from the current investigation, including the experimental observations of crack closure.

Keywords

Plastic zone Crack closure Fatigue crack Digital Image Correlation 

References

  1. 1.
    Castro, J., Meggiolaro, M.: Fatigue Design Techniques (in 3 volumes). CreateSpace, Scotts Valley (2016)Google Scholar
  2. 2.
    Wolf, E.: Fatigue crack closure under cyclic tension. Eng. Fract. Mech. 2(1), 37–45 (1970)CrossRefGoogle Scholar
  3. 3.
    Gonzáles, G., González, J., Castro, J., Freire, J.: Detecting fatigue crack closure and crack growth delays after an overload using DIC measurements. Fract. Fatigue Fail. Damage Evol. 7, 57–65 (2018)Google Scholar
  4. 4.
    Nowell, D., De Matos, P.: Application of digital image correlation to the investigation of crack closure following overloads. Procedia Eng. 2(1), 1035–1043 (2010)CrossRefGoogle Scholar
  5. 5.
    Withers, P., Lopez-Crespo, P., Mostafavi, M., Steuwer, A., Kelleher, J., Buslaps, T.: 2D mapping of plane stress crack-tip fields following an overload. Frattura ed Integrità Strutturale. 9(33), 151 (2015)CrossRefGoogle Scholar
  6. 6.
    Sousa, R., Castro, J., Lopes, A., Martha, L.: On improved crack tip plastic zone estimates based on T-stress and on complete stress fields. Fatigue Fract. Eng. Mater. Struct. 36(1), 25–38 (2013)CrossRefGoogle Scholar
  7. 7.
    Sutton, M.A., Orteu, J.J., Schreier, H.: Image correlation for shape, motion and deformation measurements: basic concepts, theory and applications. Springer US, Boston, MA (2009)Google Scholar
  8. 8.
    Camas, D., Lopez-Crespo, P., Gonzalez-Herrera, A., Moreno, B.: Numerical and experimental study of the plastic zone in cracked specimens. Eng. Fract. Mech. 185, 20–32 (2017)CrossRefGoogle Scholar
  9. 9.
    Vasco-Olmo, J., James, M., Christopher, C., Patterson, E., Díaz, F.: Assessment of crack tip plastic zone size and shape and its influence on crack tip shielding. Fatigue Fract. Eng. Mater. Struct. 39(8), 969–981 (2016)CrossRefGoogle Scholar
  10. 10.
    Du, Y., Patki, A., Patterson, E.: Monitoring crack tip plastic zone size during fatigue loading. Exp. Appl. Mech. 6, 569–573 (2011)Google Scholar
  11. 11.
    Rossi, M., Sasso, M., Chiappini, G., Mancini, E., Amodio, D.: Identification of the plastic zone using digital image correlation. Frattura ed Integrità Strutturale. 30, 552 (2014)CrossRefGoogle Scholar
  12. 12.
    VIC-3D, “®Software,” Correlated Solutions Inc. http://www.correlatedsolutions.com/. (2010)
  13. 13.
    Gonzáles, G.L., González, J.A., Castro, J.T., Freire, J.L.: A J-integral approach using digital image correlation for evaluating stress intensity factors in fatigue cracks with closure effects. Theor. Appl. Fract. Mech. 90, 14–21 (2017)CrossRefGoogle Scholar

Copyright information

© The Society for Experimental Mechanics, Inc. 2019

Authors and Affiliations

  • G. L. G. Gonzáles
    • 1
  • J. A. O. González
    • 1
  • V. E. L. Paiva
    • 1
  • J. L. F. Freire
    • 1
  1. 1.Pontifical Catholic University of Rio de Janeiro, PUC-RioRio de JaneiroBrazil

Personalised recommendations