Modelling the orthogonal cutting of UD-CFRP composites: Development of a novel cohesive zone model

The inhomogeneous and anisotropic nature of CFRP presents a challenge
achieving accurate simulations largely due to limitations of current material
constitutive relationship, in particular for predicting debonding of the matrix
and bre. Following a comprehensive review of the various published cohesive
models a new approach for representing the bre-matrix interface is proposed
for a three-dimensional FE model of orthogonal cutting of UD-CFRP. While
severe deformations of the cohesive elements are generally observed when surrounding elements fail, excessively strong bonds are typically formed when
employing surface-based cohesive behaviour. The proposed approach overcomes these limitations by employing zero thickness cohesive elements based on a traction-separation law, which are deleted from the analysis if any of
the surrounding elements fails. The FE models were validated in terms of
predicted cutting and thrust forces against published data for dierent bre
orientations. Cutting forces showed good agreement to experimental results
for 90and 135(error within 5%), while thrust forces are generally underestimated.