Advertisement

Biaxial experiments on characterization of stress-state-dependent damage in ductile metals

  • Michael BrünigEmail author
  • Moritz Zistl
  • Steffen Gerke
Production Process
  • 43 Downloads

Abstract

The paper discusses new biaxial experiments to characterize stress-state-dependent damage and fracture processes in ductile metals on different scales. To motivate the experimental program a phenomenological continuum damage model is presented demonstrating the need of experiments covering a wide range of stress states and loading histories. Biaxial experiments with the X0-specimen taken from thin metal sheets tested under different load ratios are discussed with focus on proportional and corresponding non-proportional loading paths. During the tests strain fields on the surfaces of critical regions of the specimen are monitored by digital image correlation technique elucidating formation of localized strain bands leading to damage and failure. After the experiments fracture surfaces are examined by scanning electron microscopy revealing different damage and fracture process on the micro-scale depending on the stress states and the loading histories.

Keywords

Ductile metals Damage Stress state dependence Biaxial experiments Digital image correlation Scanning electron microscopy 

Notes

Acknowledgements

The project has been funded by the Deutsche Forschungsgemeinshaft (DFG, German Research Foundation) – project number 322157331, this financial support is gratefully acknowledged. The SEM images of the fracture surfaces presented in this paper were performed at the Institut für Werkstoffe im Bauwesen, Bundeswehr University Munich and the support of Wolfgang Saur is gratefully acknowledged.

References

  1. 1.
    Bai Y, Wierzbicki T (2008) A new model of metal plasticity and fracture with pressure and Lode dependence. Int J Plast 24:1071–1096CrossRefGoogle Scholar
  2. 2.
    Bao Y, Wierzbicki T (2004) On the fracture locus in the equivalent strain and stress triaxiality space. Int J Mech Sci 46:81–98CrossRefGoogle Scholar
  3. 3.
    Benzerga AA, Leblond JB (2010) Ductile fracture by void growth to coalescence. Adv Appl Mech 44:169–305CrossRefGoogle Scholar
  4. 4.
    Bonora N, Gentile D, Pirondi A, Newaz G (2005) Ductile damage evolution under triaxial state of stress: theory and experiments. Int J Plast 21:981–1007CrossRefGoogle Scholar
  5. 5.
    Brünig M (2003) An anisotropic ductile damage model based on irreversible thermodynamics. Int J Plast 19:1679–1713CrossRefGoogle Scholar
  6. 6.
    Brünig M, Brenner D, Gerke S (2015) Stress state dependence of ductile damage and fracture behavior: experiments and numerical simulations. Eng Fract Mech 141:152–169CrossRefGoogle Scholar
  7. 7.
    Brünig M, Chyra O, Albrecht D, Driemeier L, Alves M (2008) A ductile damage criterion at various stress triaxialities. Int J Plast 24:1731–1755CrossRefGoogle Scholar
  8. 8.
    Brünig M, Gerke S, Hagenbrock V (2013) Micro-mechanical studies on the effect of the stress triaxiality and the Lode parameter on ductile damage. Int J Plast 50:49–65CrossRefGoogle Scholar
  9. 9.
    Chaboche J (1988) Continuum damage mechanics. Part I: general concepts. J Appl Mech 55:59–64CrossRefGoogle Scholar
  10. 10.
    Chow C, Wang J (1987) An anisotropic theory of continuum damage mechanics for ductile fracture. Eng Fract Mech 27:547–558CrossRefGoogle Scholar
  11. 11.
    Driemeier L, Brünig M, Micheli G, Alves M (2010) Experiments on stress-triaxiality dependence of material behavior of aluminum alloys. Mech Mater 42:207–217CrossRefGoogle Scholar
  12. 12.
    Dunand M, Mohr D (2011) On the predictive capabilities of the shear modified Gurson and the modified Mohr–Coulomb fracture models over a wide range of stress triaxialities and Lode angles. J Mech Phys Solids 59:1374–1394CrossRefGoogle Scholar
  13. 13.
    Gerke S, Adulyasak P, Brünig M (2017) New biaxially loaded specimens for analysis of damage and fracture in sheet metals. Int J Solids Struct 110:209–218CrossRefGoogle Scholar
  14. 14.
    Gerke S, Zistl M, Bhardwaj A, Brünig M (2019) Experiments with the X0-specimen on the effect of non-proportional loading paths on damage and fracture mechanisms in aluminum alloys. Int J Solids Struct 163:157–169CrossRefGoogle Scholar
  15. 15.
    Gurson AL (1977) Continuum theory of ductile rupture by void nucleation and growth: Part I - Yield criteria and flow rules for porous ductile media. J Eng Mater Technol 99:2–15CrossRefGoogle Scholar
  16. 16.
    Kachanov L (1958) On rupture time under condition of creep. Otd Techn Nauk 8:26–31Google Scholar
  17. 17.
    Lemaitre J (1985) A continuous damage mechanics model for ductile fracture. J Eng Mater Technol 107:83–89CrossRefGoogle Scholar
  18. 18.
    Lemaitre J (1996) A course on damage mechanics. Springer, Berlin HeidelbergCrossRefGoogle Scholar
  19. 19.
    Mohr D, Henn S (2007) (2007) Calibration of stress-triaxiality dependent crack formation criteria: A new hybrid experimental-numerical method. Exp Mech 47:805–820CrossRefGoogle Scholar
  20. 20.
    Tai W, Yang B (1986) A new microvoid-damage model for ductile fracture. Eng Fract Mech 25:377–384CrossRefGoogle Scholar
  21. 21.
    Tvergaard V (1990) Material failure by void growth to coalescence. Adv Appl Mech 27:83–151CrossRefGoogle Scholar

Copyright information

© German Academic Society for Production Engineering (WGP) 2019

Authors and Affiliations

  1. 1.Institut für Mechanik und StatikUniversität der Bundeswehr MünchenNeubibergGermany

Personalised recommendations