While the ladder ship unloader is digging the materials, the material that is about to enter the bucket is in limited stress state. It must conform with the equilibrium equation and yield criteria. The mechanical reaction between the bucket and the material is a planar problem for which the equilibrium equation is derived. The yield-criteria are linear MOHR-COULOMB yield criteria. The components of the digging force, when the buckets dig into the material, are: the stress in the sliding plane, the friction resistance between the buckets and the materials, and the effects of gravity of the materials on the buckets. The digging resistance is related to the properties of the material, such as cohesive force, shear stress, normal stress, internal friction angle of the material, piling density of materials, and the coefficient of friction between the buckets and the material as well as the parameters of the buckets such as the speed, acceleration, front angle and weight of the buckets and the diving force of the buckets. Because the digging resistance is a complicated function, it is very difficult to derive a mathematical solution. By means of dimensional analysis a set of equations is obtained from the dimensional analysis. By using the described model, the predicted results of digging ore obtained by simulation are in agreement with measured results.
On simulation modelling of the ladder ship unloader
Simulationsmodell des Eimerketten-Schiffsentladers
Bulk Solids Handling ; 17 , 2 ; 213-216
1997
4 Seiten, 1 Tabelle, 3 Quellen
Article (Journal)
English