Background

The flow and behaviour of granular material is an ongoing research subject for many years because of its importance in industrial processes such as bulk materials handling, comminution, mixing, consolidation, etc. A great wealth of information exists in these fields but most of the information is in the formof empirical formulas and curve fits. Soil mechanics and earthmoving are two of the historic research areas where much work was done. The empirical behaviour of soils and rocks is well documented and various numerical models were developed.

In recent years, research into the behaviour of granular materials shifted towards numerical simulation models, such as the discrete element method (DEM) and specialised continuum models. The exponential growth in the computing capability of modern computers makes it possible today to model fairly complex granular flows. The largest part of the research effort in this field is still in the optimisation of algorithms and development of contact constitutive models.

History of the GMRG

The research into granular flow at the Department of Mechanical and Mechatronic Engineering of the University of Stellenbosch started off in 1998 with a request from industry for the optimisation of dragline buckets. During the research it was realised that the interaction between granular material and the engagement tools is very poorly understood.

The granular materials research group was established with the aim to investigate the optimisation of earth-moving, mining and agricultural equipment. With financial support from industry, a three-dimensional discrete element method (DEM) simulation software package was purchased. A continuum based simulation model was also developed for granular flows using the material point method (MPM), a meshless finite element method.

Over time, through undergraduate and postgraduate projects, a range of support test equipment was developed to obtain material properties for numerical simulations. This includes a large scale shear tester. The testing facilities at the Civil Engineering department were also extensively used for material classification and small scale shear tests.