High-gradient constitutive model for granular material with random packing structure
- Univ. of Massachusetts, Amherst, MA (United States)
Granular material, such as soil, powder, ceramic material, etc., can be perceived as a collection of particles. The overall mechanical properties for granular materials depend significantly on the micro-scale geometric arrangement and on the contact stiffness between two interacting particles. A second-gradient constitutive law for granular media is derived in which stress is a function of the second-order of strain gradient. The constitutive coefficients for granular materials with isotropic packing structure are derived in explicit terms of inter-particle stiffness and particle size. In the present constitutive theory, the total number of elastic constants for the isotropic granular material is four: two of them are the usual Lame constants, the other two are associated with the second-gradient of strain. The derived constitutive relationships illustrate the important role of micro-scale properties in the macro-scale behavior. The influence of inter-particle stiffness and particle size on the response of material due to second-gradient of strain is discussed. The micro structure effects become important for dynamic problems involving short wavelengths. This paper also discusses the connection between the second-gradient theory and nonlocal theory. The second-gradient theory can be regarded as the first-order approximation of nonlocal theory.
- OSTI ID:
- 175250
- Report Number(s):
- CONF-950686--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Strain Stiffening in Random Packings of Entangled Granular Chains
Wave propagation in granular material using high gradient theory