Mastering interface delamination with advanced digital image correlation

Recently the Mechanics of Materials group developed an advanced setup for controlled mixed-mode interface delamination, which enables in-situ microscopic observation of the delamination process. However, extraction of the relevant information associated with the delamination mechanisms from these pictures is still a key challenge, especially, because (electron) microscopic images often contain much noise. The objective is here to present a robust identification method of the mechanical interface behavior.

PhD researcher: B. Blaysat
Supervisors: J. P. M. Hoefnagels, M. G. D. Geers & G. Lubineau
Institutions: KAUST & Phillips

The proposed procedure relies on the combination of two different  tools : (i) a description of the kinematics during a delamination test, based on a kinematically-admissible ‘eigenmodes’ basis that correspond to the parameters controlling the interface behavior in an analytic model of the delaminating sample. This description is then used in (ii) an advanced integrated digital image correlation algorithm, which will enables the identification of interface properties from the images.

As a first step, the method is dedicaded to pure mode I case and is validated on virtual delamination experiments, simulated using a recently developed self-adaptive cohesive zone finite element framework. The approach is analyzed on accuracy and sensitivity to noise and is now applied to copper lead frame-molding compound epoxy samples. Forthcoming studies will be focus on its extension to mixed mode.