Computer simulated deformation of compact granular assemblies

SummaryThe paper is concerned with the mechanics of granular material under quasi-equilibrium conditions. The characterisation of the microstructure of granular material is discussed and the relationship between the microstructure and the stress tensor is examined.Results from computer simulated experiments on a large, initially random, dense assembly of different sized discs are used to investigate the evolution of both stress and structure. Two tests are reported: one a constant mean stress test and the other a constant volume test. It is shown that, although the two tests were subjected to different strain histories the degree of induced structural anisotropy evolved in an identical manner.The computer simulated tests show that there also exists a statical anisotropy due to the biased distribution of contact forces within an assembly. This also evolves in the same way for both tests reported. Consequently, the evolution of the angle of internal shearing resistance with strain is found to be unique.