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Measurement of cohesive zone parameters in tough polyethylene
Author(s) -
Pandya K. C.,
Williams J. G.
Publication year - 2000
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.11308
Subject(s) - materials science , polyethylene , traction (geology) , composite material , cohesive zone model , ultimate tensile strength , plane stress , structural engineering , fracture (geology) , finite element method , mechanical engineering , engineering
The initiation, growth and final failure of the craze ahead of a crack tip generally controls the onset of crack growth in polyethylene, particularly in slow crack growth. In this research, circumferentially deep notched tensile specimens are used to analyze the evolution and failure of crazes in polyethylene under plane strain conditions. An experimental method is used wherein the traction‐separation behavior of the craze structure is measured directly in ‐ situ. Results yield a cohesive zone type analysis in which a two parameter traction curve, containing within it all information pertaining to local decohesion, fully describes the separation of the interface. Experimentally measured rate dependent trends in the work of separation (I) provide good discrimination between different grades of tough polyethylene at both high and quasi‐static test speeds, and highlight the exceptional long term behavior of one particular grade. The method also allows for the quantification of the long term behavior of each grade by more traditional stress‐time analysis.