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Numerical analysis of strain rate sensitivity in ball indentation on cohesive powder Beds

Pasha, M, Hare, C, Hassanpour, A and Ghadiri, M (2015) Numerical analysis of strain rate sensitivity in ball indentation on cohesive powder Beds CHEMICAL ENGINEERING SCIENCE, 123. pp. 92-98.

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Abstract

In the shear deformation of powder beds beyond the quasi-static regime the shear stress is dependent on the strain rate. Extensive work has been reported on the rapid chute flow of large granules but the intermediate regime has not been widely addressed particularly in the case of cohesive powders. However in industrial powder processes the powder flow is often in the intermediate regime. In the present work an attempt is made to investigate the sensitivity of the stresses in an assembly of cohesive spherical particles to the strain rate in ball indentation using the Distinct Element Method. This technique has recently been proposed as a quick and easy way to assess the flowability of cohesive powders. It is shown that the hardness, deviatoric and hydrostatic stresses within a bed, subjected to ball indentation on its free surface, are dependent on the indentation strain rate. These stresses are almost constant up to a dimensionless strain rate of unity, consistent with trends from traditional methods of shear cell testing, though fluctuations begin to increase from a dimensionless strain rate of 0.5. For dimensionless strain rates greater than unity, these stresses increase, with the increase in hardness being the most substantial. These trends correlate well with those established in the literature for the Couette device. However quantitative value of the strain rate boundaries of the regimes differ, due to differences in the geometry of shear deformation band. Nevertheless, this shows the capability of the indentation technique in capturing the dynamics of cohesive powder flow.

Item Type: Article
Divisions : Faculty of Engineering and Physical Sciences > Chemical and Process Engineering
Authors :
NameEmailORCID
Pasha, MUNSPECIFIEDUNSPECIFIED
Hare, Cc.hare@surrey.ac.ukUNSPECIFIED
Hassanpour, AUNSPECIFIEDUNSPECIFIED
Ghadiri, MUNSPECIFIEDUNSPECIFIED
Date : 17 February 2015
Identification Number : 10.1016/j.ces.2014.10.026
Copyright Disclaimer : © 2015. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Uncontrolled Keywords : Science & Technology, Technology, Engineering, Chemical, Engineering, Flowability, DEM, Indentation on powder bed, Strain rate, Cohesive powder, COHESIONLESS GRANULAR-MATERIALS, ELASTIC SOLIDS, SHEAR CELL, FLOWABILITY, CONTACT, FLOW, ASSEMBLIES, SIMULATION, ADHESION, MODEL
Related URLs :
Depositing User : Symplectic Elements
Date Deposited : 17 May 2017 13:48
Last Modified : 04 Aug 2017 11:19
URI: http://epubs.surrey.ac.uk/id/eprint/840416

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