Observation on Pattern Competition and Selection of Strain Localization in Rocks under Uniaxial Compression

Pattern competition and selection of strain localization were observed in rocks under uniaxial compression. The localization may be the trigger mechanism and an effective precursor of eventual rupture in brittle media. It is found that usually two high strain zones form before the eventual rupture. The rapidly increasing strain and strain rate within one of the high strain zones will lead to the eventual rupture of the specimen, and in the meantime, the strain and strain rate in the other high strain zone decrease rapidly. The digital speckle correlation method (DSCM) was used to measure the surface deformation fields.

Pattern Formation and Competition in the Regime of the Conserved Cubic-Quintic Nonlinear Schrödinger Equation

In this letter, the pattern formation, pattern competition and spatiotemporal chaos are first investigated in the regime of cubic-quintic nonlinear Schrödinger equation in a near-integrable Hamiltonian continuum system using a few important representative manifolds in phase space. We find that the regular pattern competition can exist in some regions of the controlled parameters, and the spatiotemporal chaos may result from stochastic competition of the patterns. This conclusion may be generalized to the systems which have the saddle structure.