The behaviour of a bed of particles under the influence of shear stress

The four characterisation groups of microscopic, state, macroscopic and behavioural properties are discussed for a packed system of particles, with particular reference to the shear strength and flow behaviour of particulate material. The relationships between the behavioural and macroscopic and between the behavioural and microscopic properties have been shown to be deficient in dBscribing what actually happens with a material under shear stress. It is postulated that a clearer understanding of the flow behaviour of particulate material will be obtained when the relationships have been obtained between the microscopic, state and macroscopic properties. The present links between these groups are reviewed and discussed. [Continues.]