title: Universal dynamic fragmentation in D dimensions.
abstract: A generic model is introduced for brittle fragmentation in D dimensions, and this model is shown to lead to a fragment-size distribution with two distinct components. In the small fragment-size limit a scale-invariant size distribution results from a crack branching-merging process. At larger sizes the distribution becomes exponential as a result of a Poisson process, which introduces a large-scale cutoff. Numerical simulations are used to demonstrate the validity of the distribution for D=2. Data from laboratory-scale experiments and large-scale quarry blastings of granitic gneiss confirm its validity for D=3. In the experiments the nonzero grain size of rock causes deviation from the ideal model distribution in the small-size limit. The size of the cutoff seems to diverge at the minimum energy sufficient for fragmentation to occur, but the scaling exponent is not universal.
authors.affiliation: Centre for Scientific Computing, P.O. Box 405, FIN-02101 Esbo, Finland.
authors.forename: J A
authors.initials: JA
authors.lastname: Aström
authors.forename: F
authors.initials: F
authors.lastname: Ouchterlony
authors.forename: R P
authors.initials: RP
authors.lastname: Linna
authors.forename: J
authors.initials: J
authors.lastname: Timonen