Discrete Element Method (DEM) simulations of elongated (i.e. needle-shaped) particles breakage in a shear field confined between two parallel plates, in analogy with processes occurring in a powder shear cell tester, were carried out. Effects of particle strength, shear rate and the compressive stress were investigated. The breakage patterns occurring in a layer of particles due to compressive and shearing stress fields are analysed in detail and compared. The results of these computational experiments reveal that when the course of particle breakage is represented in the mean particle length vs. polydispersity diagram, the breakage patterns for slow shearing and compression follow the same path that is close to the path constructed for an idealized breakage scenario, while curves for fast shearing deviate from the scenario towards higher polydispersities. (C) 2019 Elsevier B.V. All rights reserved.