Homogenization modelling for the behavior of randomly packed granules
- Fay, Spofford and Thorndike Inc., Burlington, MA (United States)
Granular material is considered as a collection of spheres with frictional contacts. Under static stress, the material deforms with two modes of particle movements; translation and rotation. As a result, micro-slip and dislocation occur at inter-particle contacts due to sliding and separation of particles. The micro-slip and dislocation at inter-particle contacts contribute to the in elastic deformation of the packing. A constitutive model for such type of material is derived considering the micro-slip and dislocations at inter-particle contacts. Since micro-slip or dislocation is characterized as displacement vectors distributed at inter-particle contacts over the material, it is necessary to relate these discrete quantities to an equivalent continuum strain field. Previous work in the literature has adopted the assumption of an uniform strain field over the entire packing or over a local group. Particle movement determined from this assumption neglects the interaction between the micro-slips, thus leads to a stiffer behavior. Microstructure of the packing must be considered in order to properly account for the interaction of micro-slips. These issues will be discussed in relation to constitutive modeling for granular material. Properties of an inter-particle contact can be determined from the elastic properties of granules using the Hertz-Mindlin contact law, Employing derived equations from micromechanics, the predicted behavior is compared with measured wave velocity and compressibility for sands.
- OSTI ID:
- 175249
- Report Number(s):
- CONF-950686--
- Country of Publication:
- United States
- Language:
- English
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