Single-fiber testing

The microindentation technique (or push-out test as opposed to the pull-out test) is a single fiber test capable of examining libers embedded in the actual composite. The... 

DiAnselmo, A., Accorsi, M.L, and DiBenedetto, A.T, (1992). The effect of an interphase on the stress and energy distribution in the embedded single fiber test. Composites Sci. Technol. 44, 215-225. 

Strength properties of rayon-polystyrene graft copolymers (single fiber tests) (108)... 

Fig. li. The change in failure at the single-fiber level as shown by the embedded single-fiber test is mirrored by the failure behavior at the macroscopic level. The increase in adhesion also tracks the same between the ITS results and 0° flexure data. 

Single fiber tests were used to evaluate the fiber-matrix adhesion. Acid/base interactions do play a role in this adhesion but are not exclusively responsible for improvements at the interface. Treatment with a siloxane coupling agent was proven to be effective in lowering the dispersive component of the carbon fibers and altering their acid/base properties, producing poorer adhesion. 

ASTM D 5103 95 Length and length distribution of man-made staple fibers (single-fiber test). 

Taking account of all the available evidence, a tenacity of 70g/tex is a reasonable middle value for a wide range of jute fibers, based on single fiber test lengths of 10 mm or less, and a time to break of 10 s. This value of tenacity is appropriate to fibers of linear density 1.8 tex, and it is important to state the linear density, because, statistically, an increase of 0.1 tex reduces the tenacity by about 1.5 g/tex. This inverse dependence of tenacity on linear density is common to most fibers and also to fine metal wires. 

Figure 23.8 Minimodule used for single fiber testing (Vu, 2001).

Due to the huge scatter of the single results, it cannot be recommended to apply both statistical treatment of the data and other approaches involving conventional micromechanical single fiber test methods. 

---