Improved variable-amplitude fatigue behavior of a glass-fiber-reinforced hybrid-toughened epoxy composite

Manjunatha, CM and Jagannathan, N and Padmalatha, K and Kinloch, AJ and Taylor, AC (2011) Improved variable-amplitude fatigue behavior of a glass-fiber-reinforced hybrid-toughened epoxy composite. Journal of Reinforced Plastics and Composites, 30 (21). pp. 1783-1793. ISSN 0731-6844

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    Abstract

    A thermosetting epoxy polymer was hybrid-modified by the addition of 9 wt.% of rubber microparticles and 10 wt.% of silica nanoparticles. The GFRP composite laminates employing the unmodified epoxy matrix (GFRP-neat), and the hybrid epoxy matrix (GFRP-hybrid), were produced by a resin-infusion technique. The experimental fatigue lives of both GFRP composites under three different variable-amplitude load sequences, namely (a) a three-step increasing block (IB), (b) a three-step decreasing block (DB), and (c) a random block (RB) load sequence derived from a three-step load block, were determined. The fatigue life of the GFRP-hybrid composite was higher than that of the GFRP-neat composite under all the three load sequence blocks investigated, by about_2.6 to_4.0 times. The matrix crack density and the stiffness reduction rate were both lower in the GFRP-hybrid composite compared to the GFRP-neat composite material. The suppressed matrix cracking and reduced delamination growth rates in the hybrid-modified epoxy matrix enhanced the fatigue life of the corresponding GFRP-hybrid composite. Using the constant-amplitude fatigue data generated at various stress ratios, the fatigue lives under these variable-amplitude load sequence blocks were predicted using empirical models. The predicted fatigue lives, although conservative, were in reasonably good agreement with the experimental results.

    Item Type: Journal Article
    Uncontrolled Keywords: variable amplitude, fatigue, hybrid composite, life prediction
    Subjects: CHEMISTRY AND MATERIALS > Composite Materials
    Division/Department: Structural Integrity Division, Structural Integrity Division, Structural Integrity Division, Other, Other
    Depositing User: Ms Indrani V
    Date Deposited: 06 Jan 2012 11:13
    Last Modified: 06 Jan 2012 11:13
    URI: http://nal-ir.nal.res.in/id/eprint/10195

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