A new powder tester to investigate the anisotropic consolidation behaviour

The anisotropic behaviour is significant for many applications in the handling of bulk solids, for instance pelleting or silo design. A new powder tester has been developed to measure the unconfined yield strength in uniaxial direction, which means consolidation and collapse stresses in the same direction, as well as to measure the anisotropic unconfined yield strength in biaxial direction, which means consolidation and collapse stresses are in orthogonal directions. The ratio between the anisotropic and the uniaxial unconfined yield strength yields the intensity of the anisotropic consolidation behaviour. The development of the tester and the development of the measurement procedures as well as first experimental results are presented in this paper.

The anisotropy of the consolidation behaviour can be quantified with a newly developed powder-tester, the so-called Anisotropy-Tester. The measured consolidation stresses in vertical or horizontal direction are nearly principal stresses as the friction between powder and walls is minimised by highly flexible membranes. The strengths are measured in vertical direction.Figure optionsDownload as PowerPoint slideResearch highlights
► We developed a new powder tester to measure the strengths of powder samples.
► The measured strengths are dependent on the direction of the compaction.
► The ratio of the strengths in two directions yields the anisotropic behaviour.
► Anisotropic consolidation behaviour varies for different consolidation stresses.