Statistical analysis of multiple cracking phenomenon of a SiO_x thin film on a polymer substrate

The progress of multiple cracking in a silicon oxide (SiO_x) film deposited onto a polyethylene terephthalate substrate was analyzed using Monte Carlo simulation. The finite-element analysis, assuming elastoplastic behavior of the polymer substrate, was conducted to calculate the stress distributions in film fragments and was used in the simulation. The Weibull parameters of the film were determined from the scatter of crack onset strain. The simulation predicted successfully the crack density and the distribution of fragment lengths during the progress of multiple cracking. The validity of the shear lag analysis based on the unique stress criterion in a previous study was also evaluated.