4.3.2 Approaches to include steel fibres into the CPM
Concept of the ‘perturbed zone’
De Larrard [1999] proposed a method to include stiff steel fibres into the CPM-model.
The perturbed volume of each grain fraction around the fibres was calculated by an
inverse analysis from experiments of Bartos & Hoy [1996]. Subtracting half of the
diameter of the grain fraction i under consideration of the fibre length, the length of a
cylindrical or a rectangular volume vP of a single fibre is obtained (Fig. 4.1). To calculate
the volume vP, this length is multiplied with the sum of the diameter of the fibre and the
diameter of the grain times a fitting factor kF. The best estimation of kF was 0.065. The
mean packing density can be calculated with Equation 4.8: