Statistical model of coating fragmentation under equibiaxial load

Abstract A statistical model of coating cracking under equibiaxial tension is proposed based on a Weibull strength distribution for the coating. Crack length and spacing distributions are derived assuming that cracks initiate in random locations and propagate straight till stopping upon encountering a geometiical obstacle (another crack). The theoretical distributions are verified by comparing with simulated cracking patterns obtained by the Monte-Carlo method. An analysis of crack patterns of SiO2 coatings on a PET film under biaxial tension is performed. Qualitative agreement with the theoretical crack spacing distribution is observed.