Scaling Laws of Stress and Strain in Brittle Fracture

A numerical realization of an elastic beam lattice is used to obtain scaling exponents relevant to the extent of damage within the controlled, catastrophic and total regimes of mode-I brittle fracture. The relative fraction of damage at the onset of catastrophic rupture approaches a fixed value in the continuum limit. This enables disorder in a real material to be quantified through its relationship with random samples generated on the computer.Comment: 4 pages and 6 figure

Fra tradisjonell forvaltningsvirksomhet til profesjonell servicebedrift : hva kjennetegner virksomheter som lykkes og hva har de gjort for å bli fremragende?

Tema for vår studie har vært å se hva som kjennetegner virksomheter som lykkes, og hva de har gjort for å bli fremragende og utgangspunktet har vært følgende problemstilling: "Hvordan endre en statlig forvaltningsvirksomhet til en profesjonell servicebedrift"

Statistical Physics of Fracture Surfaces Morphology

Experiments on fracture surface morphologies offer increasing amounts of data that can be analyzed using methods of statistical physics. One finds scaling exponents associated with correlation and structure functions, indicating a rich phenomenology of anomalous scaling. We argue that traditional models of fracture fail to reproduce this rich phenomenology and new ideas and concepts are called for. We present some recent models that introduce the effects of deviations from homogeneous linear elasticity theory on the morphology of fracture surfaces, succeeding to reproduce the multiscaling phenomenology at least in 1+1 dimensions. For surfaces in 2+1 dimensions we introduce novel methods of analysis based on projecting the data on the irreducible representations of the SO(2) symmetry group. It appears that this approach organizes effectively the rich scaling properties. We end up with the proposition of new experiments in which the rotational symmetry is not broken, such that the scaling properties should be particularly simple.Comment: A review paper submitted to J. Stat. Phy

Scaling behaviour of damage in the fracture of two-dimensional elastic beam lattices

The response of stress with strain is one of the fundamental quantities used to characterize fracture in materials. Exactly how this relationship appears depends on the microscopic structure, which can vary considerably from material to material. Presently, we study the breaking of materials where the structural disorder is varied within a broad range, using a model based on elastic beams. A large number of system sizes is then generated for each level of disorder in order to study the scaling properties of the force-displacement characteristic. Whereas maximum force and displacement is found to scale trivially, being simply proportional to system size, the scaling exponents relative to the extent of damage in the stable and unstable regimes of fracture are found to scale non-trivially. Our calculations contradict earlier findings which suggested that the scaling is universal with respect to the disorder