DEM input parameters are fitted to match a bulk observable, not derived from first principles. A parameter set calibrated against an angle of repose test constrains one point in a multi-dimensional parameter space. When the hopper geometry changes, the stress state changes, and unconstrained parameters become the dominant source of prediction error.
Jenike shear cells and ring shear testers measure the same yield locus through different mechanics. Here is how their sample, stress range, and time differences map onto the mass-flow versus funnel-flow hopper design decision, plus a checklist for choosing between them.
Both the Hausner Ratio and Carr Index reduce bulk and tapped density to a single number. The mechanism behind that number, whether aeration, particle shape, or surface cohesion, determines whether it supports a process decision or actively misleads one.
Mass flow requires hopper walls that are steep [...]
Hopper bridging is rarely random. It points to [...]
Powder caking can be predicted and, in most [...]
The angle of repose and flowability are related, [...]
Most blend failures start with segregation during transfer. [...]
Black mass is fine, conductive, and often cohesive. [...]
Powder flowability is critical to efficiency, quality, and [...]
