A Micromechanical Investigation of Instability in Particulate Materials and Higher Order Continuum Theory Assumptions
Abstract
The micropolar theory (Eringen, 1966, 1968) is a continuum version of the structural theory of Cosserat (1909). It enriches the kinematics and kinetics of continua by adding material rotations and couple stresses. Using a micropolar approach similar to Kanatani (1979), Muhlhaus and Vardoulakis (1986) explained the emergence, orientation and thickness of shear bands in granular materials. Bardet and Proubet (l992a) used a similar linear stability analysis and micropolar description, and investigated the structure of persistent shear bands in idealized granular media. They successfully described the thickness of shear bands and the relation between particle rotation and displacement within persistent shear bands. However, the coefficients of their micropolar models, based on the flow or deformation theory of plasticity, had to be set to unrealistic values to reproduce the observations. Chang et al. (1990, 1991, 1992) developed micropolar theories for granular materials based on microscopic models. They derived the micropolar constants in terms of the inter-particle stiffness, and investigated the micropolar effects on the solution of selected boundary value problems. Chang derived stress-strain relationships without examining their effects on material instability. He did not investigate the problem of strain localization as De Borst and Sluys (1992).
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 31, 1998
- Accession Number
- ADA389672
Entities
People
- Jean-pierr Bardet
Organizations
- University of Southern California