The paper presents a micromechanical representation of deformation in 2D granular materials, building upon K. Bagi’s work and the void-cell approach of M. Satake. The representation is applicable to a material region partitioned into polygonal subregions, allowing for a unique assignment of the contribution of each contact displacement to the average deformation. The author discusses the construction of the particle graph and appropriate data structures for use with the Discrete Element Method (DEM). The method is applied to a numerical simulation of a two-dimensional assembly of disks, revealing nonuniform deformation and the presence of micro-bands, thin linear zones of intense rotation, even at low strains. The results highlight the importance of considering localized deformation structures in granular materials.The paper presents a micromechanical representation of deformation in 2D granular materials, building upon K. Bagi’s work and the void-cell approach of M. Satake. The representation is applicable to a material region partitioned into polygonal subregions, allowing for a unique assignment of the contribution of each contact displacement to the average deformation. The author discusses the construction of the particle graph and appropriate data structures for use with the Discrete Element Method (DEM). The method is applied to a numerical simulation of a two-dimensional assembly of disks, revealing nonuniform deformation and the presence of micro-bands, thin linear zones of intense rotation, even at low strains. The results highlight the importance of considering localized deformation structures in granular materials.