Some investigations into the strength and flow properties of powders

Summary Results of investigations made of the strengths of powders have been found to fit a general eq. for a yield locus at constant bulk density of the form: (/C)ⁿ=/T+1, where is the applied compressive stress and is the applied shear stress. The parametern for any particular powder is independent of bulk density and can be used to classify powders according to their flow properties. Experimentally determined values of tensile strengthT and cohesionC are both shown to have a similar type of power law relationship with bulk density. The relationships between shear stress, normal stress and bulk density for powders are represented by surfaces in a 3-dimensional space analogous to a similar concept recently developed in soil mechanics. The relationships greatly simplify the laboratory measurements required for hopper design.Paper presented at a meeting of the British Society of Rheology, University of Nottingham, April 6–8, 1965.Dr. Jenike's helpful comments are appreciated.