Interface shear bond strength

Fig 3.8 shows the interface shear bond strength, tb, determined from Eq. (3.7), which is not a material constant but varies substantially with embedded fiber length, L. However, to evaluate all the relevant interface properties properly, which include the interface fracture toughness, Gic, the coefficient of friction, p, and the residual clamping stress, qo, it is necessary to obtain experimental results for a full range of L and plot these characteristic fiber stresses as a function of L. More details of the... 

Fig. 4.11. Plot of interface shear bond strength, ib, as a function of fiber length, 2L. showing the interface debond criteria, according to Eq. (4.71). After Kim et al. (1993b).

Fig. 4.15. Plots of interface shear bond strength, tb, as a function of normalized debond length, H/a, illustrating the areas corresponding to debonding only (region A), fiber fragmentation without further...

Interface shear bond strength of epoxy droplets on a UHMWPE fiber"... 

ASTM C 882 (3x6 cylinders with 45° interface 1 day shear bond strength (a 1000 psi) ... 

The filler-matrix interface The interface between filler and matrix is also crucial in terms of composite performance. The interface serves to transfer externally applied loads to the reinforcement via shear stresses over the interface. Controlling the strength of the interface is very important. Clearly, good bonding is essential if stresses are to be adequately transferred to the reinforcement and hence provide a true reinforcing function [1]. 

The average shear strength at the interface, t., whether bonded, debonded or if the surrounding matrix material is yielded, whichever occurs first, can be approximately estimated from a simple force balance equation for a constant interface shear stress (Kelly and Tyson, 1965) ... 

Apart from the elastic stress transfer at the perfectly bonded interface, another important phenomenon that must be taken into account is the stress transfer by friction, which is governed by the Coulomb friction law after the interface bond fails. Furthermore, matrix yielding often takes place at the interface region in preference to interfacial debonding if the matrix shear yield strength, Xm is significantly smaller than the apparent interface bond strength, tb. It follows thus... 

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