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Shear and normal stresses in uniaxial compaction.

Three- different groups of materials were chosen to
investigate the uniaxial compaction of particulate solids.
Dentritic and cubic sodium chloride were chosen as plastically
deforming, dicalcium phosphcte and sugar as fragmentary and
styrocell, homopolymer and copolyrinier as non-compactable
materials.
The uniaxial compaction of the materials was continuously
followed by measurement. of 1-.h e applied force,
the force transmitted radially to the die wall and the upper
punch displacement. The data obtained was presented in the
form of Mohr circles, stress pathways (shear-mean compaction
stress planes) and a three dimensional representation in
mean compaction stress, shear stress and volume change.
The yield loci evaluated from Mohr circles and
shear-mean compaction stress relationships of compactable
and non-compactable materials were found to be similar in
shape. The unloading stress profiles were however more
informative. All unloading shear-mean compaction stres's
curves of the compactable materials cross the mean compaction
stress axis to give negative values of shear stress and
reach a minimum value of T min' which was material and
compaction p.,- essure dependent. The unloading curves of
non-compactable materials gaye approximately zero shear.
The parameters evaluated from the characteristic stress
profiles were correlated to the tensile strength and
hardness of compacts.
Mathematical expressions have been proposed for the shear-mean compaction stress relationships of the materials
investigated.
TI he materials were characterised before and after
compaction in terms of specific surface aroa, porosity
and mechanical strength of compacts with ccrnpaction
pressure. / Sudan Government and
the Institution of Chemical Engineers.

Identiferoai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/3464
Date January 1982
CreatorsAbdelkarim, Abdelkarim M.
ContributorsStanley-Wood, N.G.
PublisherUniversity of Bradford, Postgraduate School of Studies in Powder Technology
Source SetsBradford Scholars
LanguageEnglish
Detected LanguageEnglish
TypeThesis, doctoral, PhD
Rights<a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>.

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