CONTINUOUS MONITORING OF THE FRAGMENTATION PHENOMENON IN SINGLE FIBER COMPOSITE-MATERIALS

A continuously monitored single-filament composite (CM-SFC) test was conducted to measure the stress at which successive fiber breaks occur in the single fiber fragmentation process. This exercise was performed with a limited number of samples of various types. The purpose was to explore the possibility of using this test as a simple alternative means of (i) measuring the size effect in single fibers, (ii) calculating the Weibull shape and scale parameters for fiber strength, (iii) calculating the fiber/matrix interfacial shear strength from the extrapolated value of fiber strength using the loading history of a single fragmentation test, rather than from the value of fiber strength extrapolated from extensive testing of single fibers at various gage lengths, as is usually done. These are aspects of the SFC test that have largely been ignored so far. The results presented here confirm the possibility of using the CM-SFC test for such purposes, with a certain degree of approximation, as discussed. Additional information supplied by this test as well as a possible effect of fiber pre-tensioning on fragmentation results (including the value of the interfacial shear strength) are also briefly discussed.