Hybrid spectral/finite element analysis of dynamic delamination of patterned thin films

Dynamic delamination of patterned thin films: a numerical study

“…The aforementioned simulations of laser-induced edge delamination events based on a hybrid spectral/FE scheme (Tran et al 2008) have shown that very little of the kinetic energy trapped in the debonded portion of the film is leaked back into the substrate. Experimental observations also pointed to the key role played by the film inertia and to the large rotations experienced by the beam during the dynamic delamination process.…”

“…It should be noted that the simulation is concluded at the time of the final crack arrest, before the internal elastic bending stresses bring the debonded film back to its initial shape along the substrate (in the absence of residual stresses and stress gradients). The ability of the simplified nonlinear beam model to capture the evolution of the key energy components during the dynamic debonding event is assessed by comparing its results to those of the more accurate and computationally expensive spectral/FE model described in Tran et al (2008). A direct comparison between the two models is provided in Fig.…”

“…Due to the boundary constraint of the film, high stresses were developed near the crack tip, resulting in either film tearing or substantial plastic dissipation. Tran et al (2008) have analyzed the dynamic mixed-mode edge delamination of patterned films, where the edge crack is initiated due to the stress concentration at the corner of the films. The kinetic energy trapped in the debonded portion of the thin film near the edge caused the interface crack to extend a distance several times the film thickness and for a significant amount of time beyond the end of the loading event.…”

“…To study the problem of anti-plane shear failure of thin film interface, Hendrickx et al (2005) have adapted a bimaterial elastodynamic spectral scheme (Geubelle and Breitenfeld 1997;Breitenfeld and Geubelle 1998) to thin film geometries. Tran et al (2008) have adopted a different numerical method, which combines a spectral scheme for the substrate and a finite element model for the film to investigate the 2D in-plane failure problem of the patterned thin film. While successfully capturing important mechanisms associated with the edge debonding problem, the hybrid 2D spectral/FE scheme is prohibitively expensive to simulate the full delamination of the patterned film strip event of interest in this present work.…”

“…The role played by residual stresses and stress gradients in the debonding process is discussed at end of the manuscript. The crack tip location during the interface delamination was captured by adapting a classical electrical resistance technique (Kandula 2008;Bjerke and Lambros 2003). A series of parallel conducting film lines made of Titanium (Ti) of constant width (200 μm) and uniform separation (200 μm) were deposited on the surface of the strip specimens, perpendicular to the direction of the crack advancement.…”