Experimental characterization of tensile properties of epoxy resin by using micro-fiber specimens
Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
SAGE Publications
Abstract
In unidirectional carbon fiber reinforced plastic (CFRP) laminates, the distance between
fibers can vary from submicron to micron length scales. The mechanical properties of the
matrix at this length scale are not well understood. In this study, processing methods have
been developed to produce high quality epoxy micro-fibers with diameters ranging from
100 to 150 um that are used for tensile testing. Five types of epoxy resin systems ranging
from standard DGEBA to high-crosslink TGDDM and TGMAP epoxy systems have been
characterized. Epoxy macroscopic specimens with film thickness of 3300 um exhibited
brittle behavior (1.7 to 4.9% average failure strain) with DGEBA resin having the highest
failure strain level. The epoxy micro-fiber specimens exhibited significant ductile behavior
(20 to 42% average failure strain) with a distinct yield point being observed in all five resin
systems. In addition, the ultimate stress of the highly cross-linked TGDDM epoxy fiber
exceeded the bulk film properties by a factor of two and the energy absorption was over 50
times greater on average. The mechanism explaining the dramatic difference in properties
are discussed and is based on size effects (the film volume is about 2000 times greater than
the fiber volume within the gage sections) and surface defects. Based on the findings
3
presented in this paper, the microscale fiber test specimens are recommended and provide
more realistic stress-strain response for describing the role of the matrix in composites at
smaller length scales.
Description
Author's final draft after peer review
Keywords
Citation
Misumi, Jun, et al. "Experimental characterization of tensile properties of epoxy resin by using micro-fiber specimens." Journal of Reinforced Plastics and Composites 35.24 (2016): 1792-1801.