Model for surface fracture induced by dynamical stress

We introduce a model where an isotropic, dynamically imposed strain induces fracture in a thin film. Using molecular-dynamics simulations, we study how the integrated fragment distribution function depends on the rate of change and magnitude of the imposed strain, as well as on temperature. A mean-field argument shows that the system becomes unstable for a critical value of the strain. We find a striking invariance of the distribution of fragments for fixed ratio of temperature and rate of change of the strain; the interval over which this invariance holds is determined by the force fluctuations at the critical value of the strain. [S1063-651X(98)50402-3].