  A phase-field approach is proposed for interface failure between two possibly
dissimilar materials. The discrete adhesive interface is regularised over a
finite width. Due to the use of a regularised crack model for the bulk
material, an interaction between the length scales of the crack and the
interface can occur. An analytic one-dimensional analysis has been carried out
to quantify this effect and a correction is proposed, which compensates
influences due to the regularisation in the bulk material. For
multi-dimensional analyses this approach cannot be used straightforwardly, as
is shown, and a study has been undertaken to numerically quantify the
compensation factor due to the interaction. The aim is to obtain reliable and
universally applicable results for crack propagation along interfaces between
dissimilar materials, such that they are independent from the regularisation
width of the interface. The method has been tested and validated on three
benchmark problems. The compensation is particularly relevant for phase-field
analyses in heterogeneous materials, where cohesive failure in the constituent
materials as well as adhesive failure at interfaces play a role.
