Single-fibre fragmentation test

In Equation (9.13), is the debonding force, Pf is the measured perimeter of the henequen fibre and 4 is the fibre-embedded length. In the case of the single fibre fragmentation test the IFSS is calculated with Equation 9.14 ... 

A tentative model has been proposed to relate the interfacial shear strength at the fibre-matrix interface, measured by a fragmentation test on single fibre composites, to the level of adhesion between both materials. This last quantity has been estimated from the surface properties of both the fibre and the matrix and was defined as the sum of dispersive and acid-base interactions. This new model clearly indicates that the micromechanical properties of a composites are mainly determined by the level of physical interactions established at the fibre-matrix interface and, in particular, by electron acceptor-donor interactions. Moreover, to a first approximation, our model is able to explain the stress transfer phenomenon through interfacial layers, such as crystalline interphases in semi-crystalline matrices and interphases of reduced mobility in elastomeric matrices. An estimation of the elastic moduli of these interphases can also be proposed. Furthermore, recent work [21] has shown that the level of interfacial adhesion plays a major role on the final performances (tensile, transverse and compressive strengths and strains) of unidirectional carbon fibre-PEEK composites. 

Multiple fragmentation test In this test, a single filament is embedded in a matrix resin and tested under tension until fragmentation into successive shorter lengths is complete and the fibre length has reached equilibrium. ... 

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