where C is a constant which depends on Poisson's ratio and Young's modulus of the fibre and matrix. As for the previous tests it is difficult to determine the onset of debonding and hence ... Also both compression tests require accurate alignment of the fibre.
An alternative method is to carry out a tensile test on a dumbell-shaped specimen containing a single fibre. Application of the load causes the fibre to fragment; the limiting final fragment length is the critical length ( Chapter10) from which the interface shear strength may be calculated.