AN EXAMINATION OF INITIAL STRESSES IN HOPPERS

Initial stresses, the stresses during filling and before discharging, measured in an experimental silo have been compared to stresses calcul ated with slice element methods (Walters, Motzkus). With the approach of Motzkus, initial stresses can be predicted fairly good, whereas Wal ters' approach yields an overestimation of the vertical stresses actin g on the feeder. Since the experimental results showed that the compre ssibility and the deformation of the bulk solid have to be taken into account, a new slice element method is worked out. The new method is b ased on slices of variable geometry, thus considering the effect of th e deformation of the bulk solid.