SIMULATION OF EXTENSIONAL CLAY FRACTURES

A spring network model has been used to study fractures in thin layers of material supported by a deformable substrate. The interactions wit h the substrate localize the stress/strain field in the material. The crossover of the shape of a single fracture in an ordered material fro m an elliptical form to a long, thin shape was studied as a function o f the substrate attachment strength. For many interacting fractures in a disordered material, the simulated fracture patterns reproduced the most important visual and statistical properties of fracture patterns from recent experiments on thin slabs of clay attached to a deformabl e substrate. In particular, the correspondence was good for a new set of scaling relations between the lengths and areas of fractures. The s hapes of the larger cracks were consistent with a self-affine curve wi th a Hurst exponent of 0.5. The dynamics of the development of the fra cture pattern corresponds qualitatively to experimental results. [S106 3-651X(98)10811-5].