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A discrete element method (DEM) model for deformable particles is established and adopted to investigate the Jenike shear process of flexible cylindrical particles with different aspect ratios (4 < Ar < 6). The DEM model is firstly validated against both experimental data and analytic solutions. Then, numerical simulations are carried out and the effects of particles shape and deformation on their friction behavior are investigated through a particle‐scale analysis on particle deformation, coordinate number, contact forces, orientation and internal friction angle. Comparative results between flexible and rigid particles under the same conditions show that the shear stress increases almost linearly with the normal load regardless of particle stiffness or shape. For both rigid and flexible particles, the shear stress and internal friction angle increase with Ar. The shear stress and internal friction angle of the flexible particles are higher than those of the rigid ones especially when Ar = 6. The latter has more inter‐particle contacts but the former has stronger contact forces. When Ar = 4 and 5, the flexible particles without many initial deformations will deform significantly during the shear process with a complex reconfiguration taking place. However, when Ar = 6, the initial deformation and internal forces of the flexible particles only change slightly during the shear process. It is thus believed that the high shear stress and internal friction angle of the flexible particles with Ar = 6 are caused by their solid packing structure which strongly enhances the capability of the particle flow to resist shear. The current knowledge will be helpful for improving the kinetic theories for granular flow for complex irregular particle flows. [ABSTRACT FROM AUTHOR]

Additive manufacturing has been widely used in the field of bonded magnets manufacturing. However, there are some key issues to be faced in order to obtain bonded magnets (BMs) with high performance. In this study, four different particle sizes of flake NdFeB powder (volume‐weighted mean diameter [VMD] of 5.60 μm, 19.21 μm, 33.25 μm, and 66.69 μm) were obtained by vibratory sieving. Flexible filaments for 3D printing BMs were produced using polyamide‐6 (PA6) as the substrate, and the production process is reported in this paper. Characterization of the performance of the 3D‐printed BMs revealed that the BMs with VMD less than 10 μm have excellent mechanical strength, but the ductility of the magnets decreases with decreasing VMD of NdFeB powder. As the NdFeB VMD decreases, the coercivity of the sample decreases and the remanence increases. This study provides a reference for the selection of filler particle size for 3D printing BMs, which can be used to develop 3D‐printed BMs with excellent performance. [ABSTRACT FROM AUTHOR]

Prestress scratching tests have been performed on polished surface of SiC ceramics under a Rockwell diamond indenter moving with uniform speed and constant normal load. Combining with acoustic emission testing, the scratching depth and the surface/subsurface damage were investigated under the action of different prestress values. The results showed that the existence of prestress should shorten the depth of median cracks and reduce the subsurface damage, moreover, with increasing prestress in a proper range, the depth of median crack was decreased and the propagation length of lateral crack was limited. [ABSTRACT FROM AUTHOR]