Fiber push-out testing

Kallas, M.N., Koss, D.A., Hahn, H.T. and Hellmann, J.R. (1992). Interfacial stress state present in a thin slice fiber push-out test. J. Mater. Sci. 27, 3821-3826. 

Fig. 4.20. Schematic presentation of rough fiber surface in a fiber push-out test. After Maekin et al.

There are many features in the analysis of the fiber push-out test which are similar to fiber pull-out. Typically, the conditions for interfacial debonding are formulated based on the two distinct approaches, i.e., the shear strength criterion and the fracture mechanics approach. The fiber push-out test can be analyzed in exactly the same way as the fiber pull-out test using the shear lag model with some modifications. These include the change in the sign of the IFSS and the increase in the interfacial radial stress, (o,z), which is positive in fiber push-out due to expansion of the fiber. These modifications are required as a result of the change in the direction of the external stress from tension in fiber pull-out to compression in fiber push-out. 

Ananth, C.R. and Chandra, N. (1995). Numerical modelling of fiber push-out test in metallic and intermetallic matrix composites mechanics of failure process. J. Composite Mater. 29, 1488-1514. 

Fig. 5.5. Normalized irKerfacial shear strength of unsized (bare) and sized E-glass fiber-epoxy matrix eomposites measured from the interfaeial testing system (ITS, equivalent to fiber push-out test), short beam shear (SBS) test, 0° flexural test and 90° flexural test. After Drown et al. (1991).

F. Rebillat, J. Lamon, R. Naslain, E. Lara-Cuizio, M. K. Ferber, T. Besmann, Interfacial bond strength in SiC/C/SiC composite materials as studied by single-fiber push-out tests, J. Am. Ceram. Soc., 81 965 (1998). 

T. A. Parthasarathy, P. D. Jero, and R. J. Kerans, Extraction of Interface Properties from the Fiber Push-out Test, Scripta Metall. et Mater., 25 [11] 2457-2462(1991). 

FIBER PUSH OUT TESTING BEFORE AND AFTER EXPOSURE RESULTS FOR AN MI SIC/SIC COMPOSITE... 

Fiber Push Out Testing Before and After Exposure Resuits for an Mi SiC/SiC Composite... 

Several samples were fabricated fiom as-received material to not only deteimine the as-received interfacial shear stress but also as an aid in practicing the sample fabrication process. After initial trials of both machining and fiber push out testing, it was decided to settle on a sample thickness of 0.35 mm. In addition to the as-received material, several samples were made available that had been tested at 1204"C with a hold stress of 165.6 MPa in air for periods of4, 250 and 1508 hours. (The test was either a creep or a 2 hour dwell fatigue test [12].) All samples were machined per the procedure outline above. All samples for this effort were the same thickness to eliminate any issue about residual stresses being a factor due to machining. 

Figure 4. Typical images of samples used for fiber push out testing...

H. Serizawa, A. Kohyama, K. Watanabe, T. Kishi and S. Sato, Elastic FEM Analysis of Fiber Push-Out Test for C/C Composites, Materials Transactions, JIM, 37 (3), 409-413 (1996). 

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