Slotted-Plate Device to Measure the Yield Behavior of Powders: FEM Analysis

We employed the slotted-plate device to measure the yield behavior of TiO2 and Y2O3 powders with different bulk densities. By considering Janssenʹs theory (Janssen, H. A. Z. Ver. deutscher Ing. 1895, 39 (35), 1045-1049), we assumed that the shear stress is linearly distributed at the powder-plate interface when the plate is placed close to the free surface of powders. Hence, the averaged shear stress along the powder-plate interface, which was measured in the experiment, denotes the shear stress at the midheight points on this surface. In addition, by considering the classical Coulomb and Mohrʹs yield function, we have derived a fourth-order algebraic equation to solve for the friction coefficient under the condition of zero cohesion. Finite element computation was performed by employing the double shearing model, which is widely used for granular materials. We implemented the constitutive equations of the double shearing model in the finite element method (FEM) program ABAQUS/Explicit (ABAQUS, Reference Manuals; Hibbitt, Karlsson and Sorensen, Inc.: Pawtucket, RI, 2001) by writing a user material subroutine. We first verified the assumption of linear distribution of shear stress along the powder-plate interface, and then we compared the computational results with that of the experimental data and found that they are in good agreement.