Single fiber pull out test

In the single fiber pull out test (SFPO), a small portion of the fiber is embedded in the bulky matrix and the interfacial strength is calculated from the peak load when the fiber is pulled out of the composite. 

The results presented in Section 4.3.6 suggest that the shear lag models based on a single fiber composite is inadequate for modelling a composite with a high fiber f). From the experimental viewpoint, to measure the relevant fiber-matrix interface properties, the fiber volume fraction in single fiber pull-out tests is always very low (i.e. Ff <0.01). This effectively means that testing with these specimens has the... 

Butler, E.P., Fuller, E.R. and Chan, H.M. (1990). Interface properties for ceramic composites from a single-fiber pull-out test. In Tailored Interfaces in Composite Materials. Mat. Res. Soc. Symp. Proc, Vol. 170, Materials Research Society, Pittsburg, PA. pp. 17 24. 

Marotzke, Ch. (1994). The elastic stress field arising in the single fiber pull-out test. Composites Sci. Technol. 50, 393 5. 

Fig. 5.27. Variation of tensile strength of copper coated carbon fibers as a function of coating thickness determined by single fiber pull-out test. After Abraham et al. (1992).

An implication of Eq. (6.3) is that debonding only occurs when < trj , or Gic < (7 d/SE[, otherwise the fiber will break prior to debonding. Other criteria for fiber fracture in single fiber pull-out test, refer to Section 4.2.4. 

Single-fiber pull-out tests, and Composite mechanical testing. 

Figure 9.11 Typical force/displacement plot from a single fiber pull-out test. (From Ref. 88, 1992, with permission from Elsevier Science.)...

Figure 3. Stress/Strain diagram and corresponding micrographs for Single fiber pull-out test under dry/wet conditions (a) Stress/Strain diagram of a single fiber (b) Micrograph of fiber breakage after pull-out for dry test (c) Micrograph of fiber breakage after pull-out for wet test.

The fiber-bundle pull-out method [19] is similar to the single-fiber pull-out method except that instead of using a single fiber, a bundle of fibers is used. A coupon is fabricated in which a bundle of fibers or a lamina of unidirectional fibers is cast in a block of matrix. Transverse notches are cut into the coupon near the end of the fiber bundle. The coupon is loaded in tension with the load applied parallel to the fiber axes. The load versus displacement curve can be monitored and the debonding point detected. In a similar manner to the way data are reduced for the single-fiber pull-out test, the interfacial shear strength between the bundle of fibers and matrix can be calculated. 

Microdroplet specimens were prepared in a similar fashion to Eichorn and Young [27], except that strands of molten Pebax 7033 were placed onto the surface of an aramid fiber [28]. For the fragmentation study, single fiber composite samples were prepared and subjected to increasing levels of strain on a Minimat tensile rig. The technique for the single fiber pull out test is described elsewhere [28]. 

Results and Discussion Single fiber pull out test... 

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