The elastic behaviour of isotropic assemblies of granular materials consist
ing of two-dimensional, bonded and nonrotating particles is studied from th
e micromechanical viewpoint. Discrete element simulations have been perform
ed of assemblies of 50,000 particles with various coordination numbers (ave
rage number of contacts per particle) and various ratios of tangential to n
ormal stiffness. Statistics, such as mean, standard deviation and probabili
ty distribution function, have been computed for geometrical quantities and
contact displacements under compressive and shearing loading. A linear rel
ation is observed between the average number of contacts of a particle and
its circumference. Average displacements do not conform to (generalised) un
iform strain as is often assumed. The probability density functions for nor
mal and tangential displacements are nearly Gaussian. None of the considere
d energies satisfy an equipartition of energy between normal and tangential
modes. (C) 2001 Elsevier Science Ltd. All rights reserved.