Changes of bulk flow properties of two different types of titanium dioxide powders are measured at room and high temperature using the High Temperature Annular Shear Cell available at the University of Salerno. Increase of the macroscopic bulk flow properties has been observed with increasing temperature, in particular with regards to the unconfined yield strength. Two different modelling approaches are discussed with the aim to relate the measured properties to the microscopic interactions between particles. The action of particle-particle interactions was firstly evaluated using the multiscale model approach proposed by Molerus [1] to predict the effect of temperature on the tensile strength of the powders. The main conclusion was that the temperature effects for materials in these conditions could only be explained by assuming a plastic deformation of the particle at the contact points. For this reason, in place of the Molerus’ purely plastic deformation model, a novel procedure to correlate microscopic interparticle forces to the measured macroscopic bulk flow properties is proposed. This is based on the theoretical modelling approach proposed by Tomas [2] that was developed to account for elasticplastic particle deformation at the contact points. The results indicate that both the model may provide a good match with the experimental data if proper values for the models’ parameters are taken into account. To this end, the sensitivity analysis for the main parameters of the models is proposed.

Analysis of Titania powders flow properties at ambient and high temperature: an experimental and modelling approach

D. Barletta;M. Poletto
2018-01-01

Abstract

Changes of bulk flow properties of two different types of titanium dioxide powders are measured at room and high temperature using the High Temperature Annular Shear Cell available at the University of Salerno. Increase of the macroscopic bulk flow properties has been observed with increasing temperature, in particular with regards to the unconfined yield strength. Two different modelling approaches are discussed with the aim to relate the measured properties to the microscopic interactions between particles. The action of particle-particle interactions was firstly evaluated using the multiscale model approach proposed by Molerus [1] to predict the effect of temperature on the tensile strength of the powders. The main conclusion was that the temperature effects for materials in these conditions could only be explained by assuming a plastic deformation of the particle at the contact points. For this reason, in place of the Molerus’ purely plastic deformation model, a novel procedure to correlate microscopic interparticle forces to the measured macroscopic bulk flow properties is proposed. This is based on the theoretical modelling approach proposed by Tomas [2] that was developed to account for elasticplastic particle deformation at the contact points. The results indicate that both the model may provide a good match with the experimental data if proper values for the models’ parameters are taken into account. To this end, the sensitivity analysis for the main parameters of the models is proposed.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11386/4716037
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