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Journal of Materials Science

, Volume 14, Issue 9, pp 2128–2138 | Cite as

Correlations of the craze profile in PMMA with Dugdale's plastic zone profile

  • S. J. Israel
  • E. L. Thomas
  • W. W. Gerberich
Papers

Abstract

The craze opening profile in PMMA has been determined as a function of stress intensity using interference optics and a special wedge loading device. An attempt was made to correlate the craze profile with the corresponding parameters (crack opening displacement and plastic zone length) predicted by the Dugdale model. Over the mid-range of stress intensities (KI=0.4 to 1.0 MPa m1/2), samples which were annealed after precracking were found to exhibit a profile similar in shape but smaller than that predicted by the Dugdale model. The lower limit of this range marks the critical stress intensity for crazing in PMMA. Both the craze length and the opening at the craze-crack interface increase with increasing stress intensity and, due to strain-hardening of the craze material, reach maximum values of about 40μm and 3μm respectively atKI=1.0 MPa m1/2. Experimental uncertainties cannot account for the profile difference and it is therefore concluded that the Dugdale model is not fully adequate to describe craze geometries in PMMA. The discrepency between the Dugdale model and the experimental data is suggested to be due to either fibril strain-hardening and/or the formation of a plane strain plastic zone ahead of the craze.

Keywords

Fibril Stress Intensity PMMA Plastic Zone Open Displacement 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman and Hall Ltd. 1979

Authors and Affiliations

  • S. J. Israel
    • 1
  • E. L. Thomas
    • 1
  • W. W. Gerberich
    • 1
  1. 1.Department of Chemical EngineeringUniversity of MinnesotaMinneapolisUSA

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