A level set approach to model directed nanocrack patterns

Abstract

Recent experiments revealed an exciting possibility of making nanowires by filling nanosacle cracks in a thin film. Exploration and practical application of the method would rely on the modeling capability to predict complex nanocracks and their geometries in heterogeneous films. This paper proposes a level set approach to investigate the formation of nanocrack patterns, which allows precise prediction of the direction of crack extension, geometry of the crack tip, and interaction between crack and other phases. The approach does not require explicit front tracking and allows for the simulation of complex crack patterns and crack intersection. An efficient iterative Fourier spectral method is applied to solve the elastic field. The propagation of the crack interface is determined by the competition between the elastic and interfacial energies. This paper investigates the cracking process in a thin film with etched spaces and stiff phases. Numerical simulations reveal that designed pre-patterns can effectively direct crack extension and suggest a significant degree of experimental control in the formation of nanocrack patterns.