Experimental Mechanics

, Volume 45, Issue 2, pp 144–152 | Cite as

Experimental determination of cohesive failure properties of a photodegradable copolymer

  • J. Abanto-Bueno
  • J. Lambros


In this paper we present a methodology to measure the material traction-separation relation for a poly(ethylene carbon monoxide) copolymer, ECO. This material exhibits a ductile-to-brittle transition when subjected to ultraviolet irradiation and undergoes a change of failure mechanism, from shear yielding to crazing, in the process. Single edge notched tension specimens of ECO irradiated for 50 h were used to generate slow-speed stable crack growth, predominantly from material crazing. Full-field measurements of the in-plane deformation around the growing crack tip were performed using the optical technique of digital image correlation. A multicamera setup was used in which simultaneous measurement of both the far-field displacement and that directly surrounding the craze was performed. The far-field results were used to obtain a value of the energy release rate supplied to the crack tip region. The near-tip results were used to extract a material traction-separation law in the regime of steady-state crack growth. A softening traction-separation relation was measured. The area under the traction-separation curve was then compared with the simultaneous far-field measurements and the agreement was very good (within 6.5%) validating the experimental methodology used.

Key Words

Cohesive properties fracture polyethylene digital image correlation multiscale testing 


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  1. 1.
    Xu, X.P., andNeedleman, A., “Numerical Simulations of Fast Crack Growth in Brittle Solids,”Journal of the Mechanics and Physics of Solids,42,(9),1397–1434 (1994).CrossRefzbMATHGoogle Scholar
  2. 2.
    Camacho, G.T. andOrtiz, M., “Computational Modeling of Impact Damage in Brittle Materials,”International Journal of Solids and Structures,33 (20–22),2899–2938 (1996).CrossRefzbMATHGoogle Scholar
  3. 3.
    Lin, G., Geubelle, P.H., andSottos, N.R., “Simulation of Fiber Debonding with Friction in a Model Composite Pushout Test,”International Journal of Solids and Structures,38 (46–47),8547–8562 (2001).CrossRefzbMATHGoogle Scholar
  4. 4.
    Barenblatt, G.I., “The Formation of Equilibrium Cracks During Brittle Fracture: General Ideas and Hypotheses, Axially Symmetric Cracks,”Applied Mathematicas and Mechanics,23,622–636 (1959).zbMATHMathSciNetCrossRefGoogle Scholar
  5. 5.
    Dugdale, D.S., “Yielding of Steel Sheets Containing Slits,”Journal of the Mechanics and Physics of Solids,8,100–108 (1960).CrossRefGoogle Scholar
  6. 6.
    Kambour, R.P., “Mechanism of Fracture in Glassy Polymers. I. Fracture Surfaces in Polymethyl Methacrylate,”Journal of Polymer Science: Part A,3,1713–1724 (1965).Google Scholar
  7. 7.
    Kambour, R.P., “Mechanism of Fracture in Glassy Polymers. II. Survey of Crazing Response During Crack Propagation in Several Polymers,”Journal of Polymer Science: Part A-2,4,17–24 (1996).CrossRefGoogle Scholar
  8. 8.
    Kambour, R.P., “Mechanism of Fracture in Glassy Polymers. III. Direct Observation of the Craze Ahead of the Propagating Crack in Poly(methyl Mechacrylate) and Polystyrene,”Journal of Polymer Science: Part A-2,4,349–358 (1966).CrossRefGoogle Scholar
  9. 9.
    Beahan, P., Bevis, M., andHull, D., “Electron-microscopy Studies of Fracture Processes in Amorphous Thermoplastics,”Polymer,14 (3),96–102 (1973).CrossRefGoogle Scholar
  10. 10.
    Kramer, E.J., “Microscopic and Molecular Fundamentals of Crazing,”Advances in Polymer Science,52,(3),1–56 (1983).CrossRefGoogle Scholar
  11. 11.
    Yang, A.C.M., Kramer, E.J., Kuo, C.C., andPhoenix, S.L., “Craze Fibril Stability and Breakdown in Polystyrene,”Macromolecules,19 (7),2010–2019 (1986).CrossRefGoogle Scholar
  12. 12.
    Berger, L.L., “On the Mechanism of Craze Fibril Breakdown in Glassy-Polymers,”Macromolecules,23 (11),2926–2934 (1990).CrossRefGoogle Scholar
  13. 13.
    Hui, C.Y., Ruina, A., Creton, C., andKramer, E.J., “Micromechanics of Crack Growth into a Craze in a Polymer Glass,”Macromolecules,25,(15),3948–3955 (1992).CrossRefGoogle Scholar
  14. 14.
    Tijssens, M.G.A., Van der Giessen, E., andSluys, L.J., “Modeling of Crazing Using a Cohesive Surface Methodology,”Mechanics of Materials,32 (1),19–35 (2000).CrossRefGoogle Scholar
  15. 15.
    Belnap, J.D. andShetty, D.K., “Micromechanics of Crack Bridging in Sapphire/Epoxy Composites,”Composites Science and Technology,58,1763–1773 (1998).CrossRefGoogle Scholar
  16. 16.
    Studer, M., Pietrzyk, J., Peters, K., Botsis, J., andGiaccari, P., “Studies on Bridging Tractions—Simultaneous Tractions and COD Measurements,”International Journal of Fracture,114,379–399 (2002).CrossRefGoogle Scholar
  17. 17.
    Brown, H.R. andWard, I.M., “Craze Shape and Fracture in Poly(methyl Methacrylate),”Polymer,14,469–475 (1973).CrossRefGoogle Scholar
  18. 18.
    Fraser, R.A.W. andWard, I.M., “Temperature Dependence of Craze Shape and Fracture in Polycarbonate,”Polymer,19,220–224 (1978).CrossRefGoogle Scholar
  19. 19.
    Peterson, T.L., Ast, D.G., andKramer, E.J., “Holographic Interferometry of Crazes in Polycarbonate,”Journal of Applied Physics,45 (10),4220–4228 (1974).CrossRefGoogle Scholar
  20. 20.
    Pandya, K.C. andWilliams, J.G., “Cohesive Zone Modeling of Crack Growth in Polymers—Part 1—Experimental Measurement of Cohesive Law,”Plastics Rubber and Composites,29 (9),439–446 (2000).Google Scholar
  21. 21.
    Pandya, K.C., Ivankovic, A., andWilliams, J.G., “Cohesive Zone Modeling of Crack Growth in Polymers—Part 2—Numerical Simulation of Crack Growth,”Plastics Rubber and Composites,29 (9),447–452 (2000).Google Scholar
  22. 22.
    Abanto-Bueno, J.L., “Fracture of a Model Functionally Graded Material Manufactured from a Photo-sensitive Polyethylene,” Ph.D. Dissertation, University of Illinois at Urbana-Champaign (2004).Google Scholar
  23. 23.
    Abanto-Bueno, J. andLambros, J., “Mechanical and Fracture Behavior of an Artificially Ultraviolet-irradiated Poly(ethylene carbon monoxide) Copolymer”,Journal of Applied Polymer Science,92 (1),139–148 (2004).CrossRefGoogle Scholar
  24. 24.
    Domininghaus, H., Plastics for Engineers: Materials, Properties and Applications, Hanser Publishers, Munich (1993).Google Scholar
  25. 25.
    Patel, J., Abanto-Bueno, J., Prebil, C., and Lambros, J., “Multiscale Fracture Experiments of a Photodegradable Polyethylene Co-polymer,” SEM Conference and Exposition Proceedings, Costa Mesa, CA (2004).Google Scholar
  26. 26.
    Lambros, J., Santare, M.H., Li, H., andSapna, G.H. III, “A Novel Technique for the Fabrication of Laboratory Scale Model Functionally Graded Materials,”EXPERIMENTAL MECHANICS 39 (3), 184–190 (1999).CrossRefGoogle Scholar
  27. 27.
    Abanto-Bueno, J. andLambros, J., “Investigation of Crack Growth in Functionally Graded Materials Using Digital Image Correlation,”Engineering Fracture Mechanics,69 (4–16),1695–1711 (2002).CrossRefGoogle Scholar
  28. 28.
    Sutton, M.A., Wolters, W.J., Peters, W.H., Ranson, W.F., andMcNeill, S.R., “Determination of Displacements Using an Improved Digital Image Correlation Method,”Image and Vision Computing,1 (3),133–139 (1983).CrossRefGoogle Scholar
  29. 29.
    Bruck, H.A., McNeill, S.R., Sutton, M.A., andPeters, W.H. III. “Digital Image Correlation Using Newton-Raphson Method of Partial-differential Correction,” EXPERIMENTAL MECHANICS 29 (3), 261–267 (1989).CrossRefGoogle Scholar
  30. 30.
    Vendroux, G. andKnauss, W.G., “Submicron Deformation Field Measurements: Part 2. Improved Digital Image Correlation,” EXPERIMENTAL MECHANICS 38 (2), 86–92 (1998).CrossRefGoogle Scholar
  31. 31.
    Eftis, J., Subramonian, N., andLiebowitz, H., “Crack Border Stress and Displacement Equations Revisited,”Engineering Fracture Mechanics,9,189–210 (1977).CrossRefGoogle Scholar
  32. 32.
    Abanto-Bueno, J. and Lambros, J., “Parameters Controlling R-curves in Functionally Graded Materials under Mode I Loading,” International Journal of Solids and Structures, submitted.Google Scholar
  33. 33.
    Neubrand, A., Chung, T-J., andRödel, J., “Experimental and Theoretical Investigation of R-curve Behavior in Al/Al 2O3 Functionally Graded Materials,”Materials Science Forum, 423–425, 262–274 (2003).Google Scholar
  34. 34.
    Estevez, R., Tijssens, M.G.A., andVan der Giessen, E., “Modeling of the Competition between Shear Yielding and Crazing in Glassy Polymers,”Journal of the Mechanics and Physics of Solids,48 (12),2585–2617 (2000).CrossRefzbMATHGoogle Scholar

Copyright information

© Society for Experimental Mechanics 2005

Authors and Affiliations

  • J. Abanto-Bueno
    • 1
  • J. Lambros
    • 2
  1. 1.Department of Mechanical EngineeringBradley UniversityPeopriaUSA
  2. 2.Department of Aerospace EngineeringUniversity of Illinois at Urbana-ChampaignUrbanaUSA

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