Finite element calculation of energy release rate for single-fibre pull-out test

A finite element model for the Single Fibre Pull Out Specimen with realistic test dimensions is introduced, which allows treatment of interface debonding as a mixed mode fracture mechanics process. A mixed mode debonding criterion is presented that uses three parameters to characterise the interface. The dominant instable interface crack extension is shown to initiate in a stable way due to a minimum in energy release rate for a very short crack length. The experimental important value of the maximum debonding force is directly related to the stable crack extension process, but proves to be strongly influenced by the interface parameters compared with the influence of the other material and geometrical specimen properties.