Content uploaded by Marc Schöneich
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All content in this area was uploaded by Marc Schöneich on Nov 09, 2015
Content may be subject to copyright.
Content uploaded by Marc Schöneich
Author content
All content in this area was uploaded by Marc Schöneich on Nov 09, 2015
Content may be subject to copyright.
Fiber-Matrix Interphase in Short Glass Fiber Composites: Experimental
Investigation and Micromechanical Modeling
M. Schöneich, F. Dinzart, H. Sabar, S. Berbenni, M. Stommel
marc.schoeneich@tu-dortmund.de
This contribution is focused on the analysis of the interphase in applied short glass fiber
reinforced thermoplastics. The interphase in fiber-matrix composites is defined as the
intersection region with modified bulk material properties [1]. Especially for FE
simulations of composites and the validation of multi-scale material modeling
approaches, the information about the existing interphase becomes important. In this
study, the interphase thickness in a short glass fiber reinforced PBT is measured by
nano-scratching. This common methodology [2] is improved and adapted to the use in
short fiber composite specimens. As shown in Figure 1, scratches in different directions
over the matrix-fiber transition are performed. Thereby, the measured range of
interphase thickness represents the inhomogeneity of the interphase. In addition, a
comparison of the interphase and the fiber sizing thickness shows a significant larger
interphase.
Using the entirety of the determined information, the interphase volume fraction of the
entire composite is calculated and inserted in a double coated material model, originally
introduced by Hori and Nemat-Nasser [3]. The present study extends this model to the
application on a double inclusion consisting of an elastic fiber surrounded by a
viscoelastic interphase, embedded in a viscoelastic matrix. The developed model is
compared to other existing approaches and finally validated in case of the present
thermoplastic glass fiber composite.
In summary, this study provides an experimental distinction between fiber sizing and
interphase thickness and contributes to the improved description of injection molded
composites in applied material modeling.
[1] Moginger B, Lutz C, Polsak A, Muller U. Morphological-Studies of Deformed
Polybutylene Terephthalate (Pbt). Colloid Polym Sci. 1991;269(6):535-542.
[2] Hodzic A, Kim JK, Stachurski ZH. The nano-scratch technique as a novel method
for measurement of an interphase width. J Mater Sci Lett. 2000;19(18):1665-1667.
[3] Hori M, Nemat-Nasser S. Double-Inclusion Model and Overall Moduli of
Multiphase Composites. Mech Mater. 1993;14(3):189-206.
Figure 1: Performed nano-scratches to
determine the interphase thickness in the
cutting plane between the fiber and the matrix