Exactly solvable models of material breakdown.

Abstract

We present the solutions to two simple models for the brittle failure of materials containing random flaws. These solutions provide support for simple scaling theories we had previously developed for more complex models, and refute recent claims that models with random dilution scale in a manner similar to a disorderless material. In particular, we find that for these models, the asymptotic size effect in the average strength is logarithmic, and the failure distribution is of an exponential of an exponential form (often with an algebraic prefactor). The method of solution is also interesting. The failure probability of the quasi-one-dimensional models we solve can be written in terms of a transition matrix introduced by Harlow. For large sample sizes, the largest eigenvalue of this transition matrix approaches one, and our solution rests on a perturbative expansion of the largest eigenvalue about one. The small and intermediate lattice behavior of the model is analyzed by using sparse matrix methods to find the largest eigenvalue of the transition matrix, and the trace of powers of the transition matrix.