HR: 0800h
AN: MR31C-0518    [Abstracts]
TI: Stress Transfer During Pressure Solution Compression of Neighboring Axi-Symmetric Asperities Pressed Against a Flat Semi-Infinite Solid
AU: Bernabe, Y
EM: yvb@mit.edu
AF: MIT, EAPS room 54-722, Cambridge, MA 02139,
AU: * Evans, B
EM: brievans@mit.edu
AF: MIT, EAPS room 54-722, Cambridge, MA 02139,
AB: In a previous work, we developed a numerical model of compression by pressure solution (PS) of a single axi- symmetric asperity pressed against a flat semi-infinite solid. The dissolution rate along the contact was determined by (1) computing the normal stress distribution from the present shape of the asperity, and (2) solving the diffusion equation inside the fluid saturated solid-solid interface, including local dissolution source terms corresponding to the stress field previously determined. The change in shape of the asperity during an infinitesimal time interval can then be calculated and the entire procedure repeated as many times as desired. Our results showed that, as the contact flattens and grows during PS, the initial elastic deformation is partially relaxed and the stress transferred from the contact centre to the edge. Our current goal is to demonstrate that, among a population of asperities, stress can also be transferred from one contact to another and that the overall compaction rate can be significantly affected by this process. For this purpose we extended our previous numerical model to simulate PS of two spherical asperities simultaneously pressed against a flat semi-infinite solid. We considered two cases: a) identical asperities with different initial (unstressed) separations with respect to the flat solid, b) asperities with different radii of curvature and identical initial separation. In both cases, stress was transferred from the most strained asperity to the least, and the overall PS displacement rate was decreased. We conclude that elastic stress transfer should be taken into account in determining the overall compaction rate, particularly for granular aggregates that are characterized by very broad distributions of both asperity separation and radius of curvature.
DE: 5120 Plasticity, diffusion, and creep
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting