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Crack tip damage analysis in fatigue fracture of epoxy resin
Author(s) -
Wang X.,
Sehanobish K.,
Moet A.
Publication year - 1988
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.750090302
Subject(s) - materials science , epoxy , composite material , fracture mechanics , crack closure , strain energy release rate , fracture (geology) , fractal dimension , crack growth resistance curve , damage mechanics , structural engineering , fractal , finite element method , mathematics , mathematical analysis , engineering
The application of the crack layer theory to fatigue crack propagation (FCP) in epoxy is discussed. A crack tip damage evolution coefficient μ is introduced to assess the extent of damage as a fraction of the damage associated with critical crack propagation. The results can be expressed in the form\documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{d\ell }}{{dN}} = \frac{{\beta G_1^2 }}{{\mu G_{1c} - G_1 }} $$\end{document}where dl / dN is the rate of FCP, G 1 is the energy release rate whose critical value is G 1 c , and β is a phenomenological constant. Although no damage was detected from microscopic analyses, μ increases fivefold during stable crack propagation. Fractal analysis of fracture surface profiles provides a quantitative measure of the roughness associated with crack advance. The fractural measure d is found to evolve in a similar fashion as μ, suggesting the applicability of d to quantify crack tip damage evolution.