E-Glass/DGEBA/m-PDA Single Fiber Composites: The Effect of Strain Rate on Interfacial Shear Strength Measurements

Published

June 1, 2000

Author(s)

Gale A. Holmes, R C. Peterson, Donald L. Hunston, Walter G. McDonough

Abstract

In this paper, precise measurements of fiber break regions formed during the single fiber fragmentation testing procedure have been made for E-glass/diglycidyl ether of bisphenol-A (DGEBA)/meta-phenylenediamine (m-PDA) single fiber fragmentation test (SFFT) specimens. From these measurements, the location and size of each fiber fragment was determined and the resulting information used to construct fragmentation maps of the tested fiber. By comparing these maps, the fragmentation process supports a random process. Since the interfacial shear strength (IFSS) or the interfacial shear stress transfer coefficient (I-STC) is obtained from the fragmentation data at saturation, frequency histograms of the E-glass/DGEBA/m-PDA saturated fragmentation data were constructed to determine the reproducibility of the fragmentation process. For the testing protocols used in this research, the E-glass/DGEBA/m-PDA frequency histograms of the fragment lengths were found to be generally reproducible. However, when the effective strain rate of the test was altered by changing the dwell time between strain increments, the fragment distribution at saturation of the E-glass/DGEBA/m-PDA SFFT specimens changed. The direction of the change was found to be inconsistent with the effect one would expect when one considers only the nonlinear viscoelastic behavior of the matrix. However, the magnitude of the change observed in the E-glass/DGEBA/m-PDA SFFT specimens is not universal. Fragmentation data obtained on E-glass/polyisocyanurate SFFT specimens revealed a much smaller change with the same testing protocol. This result occured even though fiber fragmentation occurs, as in the DGEBA/m-PDA matrix, when the polyisocyanurate matrix is exhibiting nonlinear viscoelastic behavior. The implication of these results for interfacial shear strength measurements is discussed.

Citation

Polymer Composites

Volume

12

Issue

No. 3

Pub Type

Journals

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Keywords

E-glass fibers, epoxy resin, fiber fragmentation, interface, interphase, nonlinear viscoelasticity, polyisocyanurate resin

Citation

Holmes, G. , Peterson, R. , Hunston, D. and McDonough, W. (2000), E-Glass/DGEBA/m-PDA Single Fiber Composites: The Effect of Strain Rate on Interfacial Shear Strength Measurements, Polymer Composites, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=851549 (Accessed April 26, 2024)