Degree Name

Doctor of Philosophy


Department of Civil and Mining Engineering


Storing and handling of bulk materials are essential aspects of grain, chemical and mining operations. Problems that commonly occur in silo operation mainly include flow blockages and structural failure of silos, which reduce the silo capacity and cause high maintenance cost. In most cases the problems occur principally due to inadequate design analysis together with a lack of knowledge of dynamic behaviour of the bulk material - containment structure system during the discharge of materials from silos.

thesis focusses on the simulation of the filling and the discharge process of bulk materials in silos. Emphasis has been placed on the development of the numerical methods for the prediction of bulk material pressures on silo walls and the internal stresses in silo shells under both static and dynamic conditions.

motion of bulk materials flowing through silos is modelled as the motion of a no-tension, viscous, elastic-plastic material. A s large deformation occurs during discharge of the material, geometry nonlinearity is considered in the analysis. A finite element method formulated in terms of velocity as the primary variable is developed for the simulation of the flow of bulk materials and the structural response of the silo shell. The behaviour of the flowing bulk material is coupled with the behaviour of the containment structure by the contact condition of the bulk material and the silo wall. A computer program has been developed for the analysis.

Experiments have been carried out to verify the numerical model. An automatic monitoring system has been developed for the measurement of the pressure on silo walls. The data processing method based on a power spectrum analysis is employed to separate the random noise from the original signals. The experimental results have shown that the developed numerical models can predict the bulk material pressures on silo walls in a satisfactory manner.

method of analysis has been applied to simulate the discharge of bulk material from silos. Distribution of wall pressures and internal stresses in silo shells have been computed and presented in the thesis.



Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.