000004803 001__ 4803
000004803 005__ 20141119144554.0
000004803 04107 $$aeng
000004803 046__ $$k2002-06-02
000004803 100__ $$aChalla, Vennela
000004803 24500 $$aCONDITIONS FOR LOCALIZED COMPACTION OF POROUS GRANULAR MATERIALS

000004803 24630 $$n15.$$pProceedings of the 15th ASCE Engineering Mechanics Division Conference
000004803 260__ $$bColumbia University in the City of New York
000004803 506__ $$arestricted
000004803 520__ $$2eng$$aCompaction bands are a form of localized deformation found in both field and laboratory specimens of high porosity rock. These bands consist of planar zones of pure compressional deformation that form perpendicular to the direction of maximum compression. Recent experimental results indicate that compaction bands and/or shear bands (angled to the direction of maximum compression) occur in high porosity sandstone during a transitional loading regime where multiple damage mechanisms may be active. Therefore, a two-yield surface constitutive model is employed to examine conditions for localized deformation. The first yield surface corresponds to a dilatant, frictional mechanism, while the second is a yield surface cap, which corresponds to a compactant mechanism. A bifurcation approach to localization is used, revealing that localization conditions are strongly influenced by the choice of constitutive relation. Using a single yield surface constitutive model shear bands, but not the observed compaction bands, are predicted. However, the two-yield surface model predicts both experimentally observed band types for reported values of key material parameters. Additionally, the shear band angles predicted by the two-yield surface model are in general agreement with experimentally observed shear band angles.

000004803 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000004803 653__ $$aCompaction Bands, Shear Bands, Constitutive Models

000004803 7112_ $$a15th ASCE Engineering Mechanics Division Conference$$cNew York (US)$$d2002-06-02 / 2002-06-05$$gEM2002
000004803 720__ $$aChalla, Vennela$$iIssen, Kathleen A.
000004803 8560_ $$ffischerc@itam.cas.cz
000004803 8564_ $$s129021$$uhttp://invenio.itam.cas.cz/record/4803/files/359.pdf$$yOriginal version of the author's contribution as presented on CD, .
000004803 962__ $$r4594
000004803 980__ $$aPAPER