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Title: MESO-SCALE SIMULATIONS OF COMPACTION WAVES IN A GRANULAR BED

A granular bed provides an extreme example of a heterogeneous material. Behind a moderate strength wave, the shock compression in a granular material is due to squeezing out pore space rather than an increase in the density of individual grains. This type of shock is known as a compaction wave. The key properties of compaction waves are displayed in mesomechanics simulations--continuum mechanics calculations in which individual grains are resolved. Fluctuations in hydrodynamic quantities occur behind the wave front due to stress concentrations at the contact between grains exceeding the yield strength and leading to localized plastic flow. Nevertheless, average wave profiles have the appearance of a dispersed shock wave, and for the most part the fluid mechanics equations, with the addition of a porosity variable, can be used as a homogenized model to describe the behavior of a granular bed. However, some aspects of the wave structure are not accounted for by the homogenized model. These include dispersion of weak waves and an elastic precursor for intermediate strength waves.
Authors:
Publication Date:
OSTI Identifier:
780526
Report Number(s):
LA-UR-01-2211
TRN: AH200123%%128
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: Conference title not supplied, Conference location not supplied, Conference dates not supplied; Other Information: PBD: 1 May 2001
Research Org:
Los Alamos National Lab., NM (US)
Sponsoring Org:
US Department of Energy (US)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPRESSION; FLUCTUATIONS; FLUID MECHANICS; GRANULAR MATERIALS; HYDRODYNAMICS; PLASTICS; POROSITY; PRECURSOR; SHOCK WAVES; YIELD STRENGTH