Disorder and plasticity in the fragmentation of coatings - art. no. 016109

Using a one-dimensional model that takes into account ideal plasticity of t he surface layer, we investigate the fragmentation of thin coatings under u niaxial tension. The coating is modeled as a chain of plastically deforming elements that are connected via leaf springs to a uniformly stretched subs trate. Each coating element can only withstand a maximum elongation, which is randomly distributed. From simulations of the fragmentation process we f ind that the average crack spacing <L > scales with applied strain epsilon, i.e., <L > proportional to epsilon (-kappa). Simulations and analytical ar guments show that the scaling exponent kappa depends on the disorder parame ters of the model.